Re: [RFC] coccicheck: add a test for repeat memory fetches

From: Julia Lawall
Date: Tue Jan 10 2017 - 01:06:17 EST

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On Mon, 9 Jan 2017, Kees Cook wrote:

> Okay, this adds a few tests, for people to examine.
>
> reusercopy-cook.cocci:
> My original test, with recent updates from Julia.
>
> reusercopy-wang.cocci:
> This is Pengfei's test, but with heavily modified reporting to fit in the
> kernel coccicheck target, and with all the getuser checks removed so that
> Julia's size test could be added (this lets us compare the results between
> this and my original test).

Thanks for the update.

I'm not enthusiastic about all the python filtering. It would be better
to try to put it into the pattern matching rules.

I'm not sure what is the point of func in the various rules. Is there a
need to ensure that the pattern appears only once in a function definition?

I'll look at this in more detail this evening, and try to remove more false
positives. If you know of some specifically, please let me know what they are.

thanks,
julia

>
> regetuser-wang.cocci:
> This is Pengfei's get_user() tests only (to compare against hits from just
> the copy_from_user() tests).
>
> Comparing reusercopy-cook.cocci with reusercopy-wang.cocci:
> -./arch/ia64/kernel/perfmon.c:4833
> +./arch/powerpc/kernel/signal_32.c:742
> +./arch/powerpc/kernel/signal_32.c:850
> ./arch/powerpc/platforms/powernv/opal-prd.c:248
> ./drivers/acpi/custom_method.c:54
> -./drivers/firmware/efi/test/efi_test.c:617
> -./drivers/hid/hid-picolcd_debugfs.c:283
> +./drivers/gpu/drm/radeon/radeon_cs.c:635
> ./drivers/hwtracing/stm/core.c:580
> ./drivers/isdn/i4l/isdn_ppp.c:875
> ./drivers/md/dm-ioctl.c:1741
> -./drivers/misc/mic/vop/vop_vringh.c:775
> +./drivers/md/md.c:7030
> +./drivers/misc/lkdtm_usercopy.c:106
> +./drivers/misc/lkdtm_usercopy.c:160
> +./drivers/misc/lkdtm_usercopy.c:232
> ./drivers/misc/mic/vop/vop_vringh.c:944
> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2159
> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2257
> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2302
> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2342
> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2365
> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2406
> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2439
> +./drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c:2491
> +./drivers/net/hamradio/yam.c:981
> +./drivers/net/hamradio/yam.c:997
> +./drivers/net/tun.c:2021
> +./drivers/net/tun.c:2152
> +./drivers/net/tun.c:2168
> +./drivers/net/tun.c:2211
> ./drivers/platform/chrome/cros_ec_dev.c:185
> ./drivers/scsi/3w-9xxx.c:688
> ./drivers/scsi/3w-sas.c:761
> ./drivers/scsi/3w-xxxx.c:920
> ./drivers/scsi/aacraid/commctrl.c:117
> ./drivers/scsi/megaraid.c:3465
> +./drivers/scsi/mpt3sas/mpt3sas_ctl.c:2309
> +./drivers/scsi/sg.c:422
> ./drivers/staging/lustre/lustre/llite/llite_lib.c:2491
> -./kernel/kexec_core.c:775
> -./kernel/kexec_core.c:838
> +./lib/test_kasan.c:401
> +./net/wireless/wext-core.c:809
>
> So, a couple false positives (kernel/kexec_core.c) are detected and ignored
> with the larger test.
>
> And the getuser-only test shows:
>
> ./arch/frv/kernel/traps.c:145
> ./arch/frv/kernel/traps.c:171
> ./arch/frv/kernel/traps.c:194
> ./arch/frv/kernel/traps.c:218
> ./arch/frv/kernel/traps.c:242
> ./arch/frv/kernel/traps.c:266
> ./arch/frv/kernel/traps.c:290
> ./arch/mips/kernel/traps.c:1138
> ./arch/powerpc/kernel/signal_32.c:1196
> ./drivers/staging/rtl8712/rtl871x_ioctl_linux.c:1842
> ./net/compat.c:167
> ./net/decnet/af_decnet.c:1586
> ./net/ipv4/tcp.c:2921
> ./net/ipv4/tcp.c:2939
> ./net/ipv4/tcp.c:2958
> ./net/ipv4/tcp.c:2988
> ./net/ipv4/tcp.c:3034
> ./sound/oss/swarm_cs4297a.c:1472
>
> I've been running them with:
>
> make coccicheck V=1 COCCI=scripts/coccinelle/$name.cocci MODE=report
>
> Regardless, this is still a pretty noise set of tests...
>
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
> scripts/coccinelle/tests/regetuser-wang.cocci | 391 +++++++++++++++++++++++++
> scripts/coccinelle/tests/reusercopy-cook.cocci | 49 ++++
> scripts/coccinelle/tests/reusercopy-wang.cocci | 389 ++++++++++++++++++++++++
> 3 files changed, 829 insertions(+)
> create mode 100644 scripts/coccinelle/tests/regetuser-wang.cocci
> create mode 100644 scripts/coccinelle/tests/reusercopy-cook.cocci
> create mode 100644 scripts/coccinelle/tests/reusercopy-wang.cocci
>
> diff --git a/scripts/coccinelle/tests/regetuser-wang.cocci b/scripts/coccinelle/tests/regetuser-wang.cocci
> new file mode 100644
> index 000000000000..529232089e91
> --- /dev/null
> +++ b/scripts/coccinelle/tests/regetuser-wang.cocci
> @@ -0,0 +1,391 @@
> +/// Recopying from the same user buffer frequently indicates a pattern of
> +/// Reading a size header, allocating, and then re-reading an entire
> +/// structure. If the structure's size is not re-validated, this can lead
> +/// to structure or data size confusions.
> +///
> +// Confidence: Moderate
> +// Copyright: (C) 2013 Kees Cook, Chromium.
> +// Copyright: (C) 2016 Pengfei Wang.
> +// License: GPLv2.
> +// URL: http://coccinelle.lip6.fr/
> +// Comments:
> +// Options: --no-includes --include-headers
> +
> +virtual report
> +virtual org
> +virtual context
> +
> +@initialize:python@
> +@@
> +# -------------------------Post Matching Process--------------------------
> +def post_match_process(rule,p1,p2,src,ptr):
> + filename = p1[0].file
> + first = int(p1[0].line)
> + second = int(p2[0].line)
> +
> + src_str = str(src)
> + ptr_str = str(ptr)
> + #print "src1:", src_str
> + #print "src2:", ptr_str
> + #print "first:", first
> + #print "second:", second
> +
> + # Remove loop case, first and second fetch are not supposed to be
> + # in the same line.
> + if first == second:
> + return
> +
> + # Remove reverse loop case, where first fetch behind second fetch
> + # but in last loop .
> + if first > second:
> + return
> +
> + # Remove case of get_user(a, src++) or get_user(a, src + 4)
> + if src_str.find("+") != -1 or ptr_str.find("+") != -1:
> + return
> +
> + # Remove case of get_user(a, src[i])
> + if src_str.find("[") != -1 or ptr_str.find("[") != -1:
> + return
> +
> + # Remove case of get_user(a, src--) or get_user(a, src - 4)
> + if src_str.find("-") != -1 and src_str.find("->") == -1:
> + return
> + if ptr_str.find("-") != -1 and ptr_str.find("->") == -1:
> + return
> +
> + # Remove false matching of src ===> (int*)src , but leave
> + # function call like u64_to_uptr(ctl_sccb.sccb)
> + if src_str.find("(") == 0 or ptr_str.find("(") == 0:
> + return
> +
> + coccilib.report.print_report(p2[0],
> + "potentially dangerous second get_user() (rule %d: line %d vs line %d)" %
> + (rule, first, second))
> +
> +
> +//-----------------Pattern Matching Rules-----------------------------------
> +//------------------------------- case 1: normal case without src assignment
> +@ rule1 disable drop_cast exists @
> +expression addr,exp1,exp2,src,offset;
> +position p1,p2;
> +identifier func;
> +type T1,T2;
> +@@
> + func(...){
> + ...
> +(
> + get_user(exp1, (T1)src)@p1
> +|
> + get_user(exp1, src)@p1
> +|
> + __get_user(exp1, (T1)src)@p1
> +|
> + __get_user(exp1, src)@p1
> +)
> + ... when any
> + when != src = addr
> + when != src ++
> + when != src --
> + when != src += offset
> + when != src -= offset
> + when != src = src + offset
> + when != src = src - offset
> +
> +(
> + get_user(exp2, (T2)src)@p2
> +|
> + get_user(exp2, src)@p2
> +|
> + __get_user(exp2,(T2)src)@p2
> +|
> + __get_user(exp2, src)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p11 << rule1.p1;
> +p12 << rule1.p2;
> +s1 << rule1.src;
> +@@
> +
> +if p11 and p12:
> + post_match_process(1, p11, p12, s1, s1)
> +
> +//----------------------------------- case 2: ptr = src at beginning, ptr first
> +@ rule2 disable drop_cast exists @
> +identifier func;
> +expression addr,exp1,exp2,src,ptr,offset;
> +position p0,p1,p2;
> +type T0,T1,T2;
> +@@
> +
> +
> + func(...){
> + ...
> +(
> + ptr = (T0)src@p0 // potential assignment case
> +|
> + ptr = src@p0
> +)
> + ...
> +(
> + get_user(exp1, (T1)ptr)@p1
> +|
> + get_user(exp1, ptr)@p1
> +|
> + __get_user(exp1, (T1)ptr)@p1
> +|
> + __get_user(exp1, ptr)@p1
> +)
> + ...
> + when != src = addr
> + when != src ++
> + when != src --
> + when != src += offset
> + when != src -= offset
> + when != src = src + offset
> + when != src = src - offset
> +(
> + get_user(exp2, (T2)src)@p2
> +|
> + get_user(exp2, src)@p2
> +|
> + __get_user(exp2,(T2)src)@p2
> +|
> + __get_user(exp2, src)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p21 << rule2.p1;
> +p22 << rule2.p2;
> +p2 << rule2.ptr;
> +s2 << rule2.src;
> +@@
> +if p21 and p22:
> + post_match_process(2, p21, p22, s2, p2)
> +//------------------------- case 3: ptr = src at beginning, src first
> +@ rule3 disable drop_cast exists @
> +identifier func;
> +expression addr,exp1,exp2,src,ptr,offset;
> +position p0,p1,p2;
> +type T0,T1,T2;
> +@@
> +
> +
> + func(...){
> + ...
> +(
> + ptr = (T0)src@p0 // potential assignment case
> +|
> + ptr = src@p0
> +)
> + ...
> +(
> + get_user(exp1, (T1)src)@p1
> +|
> + get_user(exp1, src)@p1
> +|
> + __get_user(exp1, (T1)src)@p1
> +|
> + __get_user(exp1, src)@p1
> +)
> + ...
> + when != src = addr
> + when != src ++
> + when != src --
> + when != src += offset
> + when != src -= offset
> + when != src = src + offset
> + when != src = src - offset
> +(
> + get_user(exp2, (T2)ptr)@p2
> +|
> + get_user(exp2, ptr)@p2
> +|
> + __get_user(exp2,(T2)ptr)@p2
> +|
> + __get_user(exp2, ptr)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p31 << rule3.p1;
> +p32 << rule3.p2;
> +p3 << rule3.ptr;
> +s3 << rule3.src;
> +@@
> +if p31 and p32:
> + post_match_process(3, p31, p32, s3, p3)
> +//----------------------------------- case 4: ptr = src at middle
> +
> +@ rule4 disable drop_cast exists @
> +identifier func;
> +expression addr,exp1,exp2,src,ptr,offset;
> +position p0,p1,p2;
> +type T0,T1,T2;
> +@@
> +
> +
> + func(...){
> + ...
> +(
> + get_user(exp1, (T1)src)@p1
> +|
> + get_user(exp1, src)@p1
> +|
> + __get_user(exp1, (T1)src)@p1
> +|
> + __get_user(exp1, src)@p1
> +)
> + ...
> + when != src = addr
> + when != src ++
> + when != src --
> + when != src += offset
> + when != src -= offset
> + when != src = src + offset
> + when != src = src - offset
> +
> +(
> + ptr = (T0)src@p0 // potential assignment case
> +|
> + ptr = src@p0
> +)
> + ...
> + when != ptr = addr
> + when != ptr ++
> + when != ptr --
> + when != ptr += offset
> + when != ptr -= offset
> + when != ptr = ptr + offset
> + when != ptr = ptr - offset
> +
> +(
> + get_user(exp2, (T2)ptr)@p2
> +|
> + get_user(exp2, ptr)@p2
> +|
> + __get_user(exp2,(T2)ptr)@p2
> +|
> + __get_user(exp2, ptr)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p41 << rule4.p1;
> +p42 << rule4.p2;
> +p4 << rule4.ptr;
> +s4 << rule4.src;
> +@@
> +if p41 and p42:
> + post_match_process(4, p41, p42, s4, p4)
> +//----------------------------------- case 5: first element, then ptr, copy from structure
> +@ rule5 disable drop_cast exists @
> +identifier func, f1;
> +expression addr,exp1,exp2,src,offset;
> +position p1,p2;
> +type T1,T2;
> +@@
> +
> +
> + func(...){
> + ...
> +(
> + get_user(exp1, (T1)src->f1)@p1
> +|
> + get_user(exp1, src->f1)@p1
> +|
> + get_user(exp1, &(src->f1))@p1
> +|
> + __get_user(exp1, (T1)src->f1)@p1
> +|
> + __get_user(exp1, src->f1)@p1
> +|
> + __get_user(exp1, &(src->f1))@p1
> +)
> + ...
> + when != src = addr
> + when != src ++
> + when != src --
> + when != src += offset
> + when != src -= offset
> + when != src = src + offset
> + when != src = src - offset
> +(
> + get_user(exp2,(T2)src)@p2
> +|
> + get_user(exp2,src)@p2
> +|
> + __get_user(exp2,(T2)src)@p2
> +|
> + __get_user(exp2,src)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p51 << rule5.p1;
> +p52 << rule5.p2;
> +s5 << rule5.src;
> +e5 << rule5.f1;
> +@@
> +if p51 and p52:
> + post_match_process(5, p51, p52, s5, e5)
> +
> +
> +//---------------------- case 6: first element, then ptr, copy from pointer
> +@ rule6 disable drop_cast exists @
> +identifier func, f1;
> +expression addr,exp1,exp2,src,offset;
> +position p1,p2;
> +type T1,T2;
> +@@
> + func(...){
> + ...
> +(
> + get_user(exp1, (T1)src.f1)@p1
> +|
> + get_user(exp1, src.f1)@p1
> +|
> + get_user(exp1, &(src.f1))@p1
> +|
> + __get_user(exp1, (T1)src.f1)@p1
> +|
> + __get_user(exp1, src.f1)@p1
> +|
> + __get_user(exp1, &(src.f1))@p1
> +)
> + ...
> + when != &src = addr
> + when != &src ++
> + when != &src --
> + when != &src += offset
> + when != &src -= offset
> + when != &src = &src + offset
> + when != &src = &src - offset
> +(
> + get_user(exp2,(T2)&src)@p2
> +|
> + get_user(exp2,&src)@p2
> +|
> + __get_user(exp2,(T2)&src)@p2
> +|
> + __get_user(exp2,&src)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p61 << rule6.p1;
> +p62 << rule6.p2;
> +s6 << rule6.src;
> +e6 << rule6.f1;
> +@@
> +if p61 and p62:
> + post_match_process(6, p61, p62, s6, e6)
> diff --git a/scripts/coccinelle/tests/reusercopy-cook.cocci b/scripts/coccinelle/tests/reusercopy-cook.cocci
> new file mode 100644
> index 000000000000..b0a71f95bdbf
> --- /dev/null
> +++ b/scripts/coccinelle/tests/reusercopy-cook.cocci
> @@ -0,0 +1,49 @@
> +/// Recopying from the same user buffer frequently indicates a pattern of
> +/// Reading a size header, allocating, and then re-reading an entire
> +/// structure. If the structure's size is not re-validated, this can lead
> +/// to structure or data size confusions.
> +///
> +// Confidence: Moderate
> +// Copyright: (C) 2013 Kees Cook, Chromium. GPLv2.
> +// URL: http://coccinelle.lip6.fr/
> +// Comments:
> +// Options: --no-includes --include-headers
> +
> +virtual report
> +virtual org
> +virtual context
> +
> +@ok@
> +position p;
> +expression src,dest;
> +@@
> +
> +copy_from_user@p(&dest, src, sizeof(dest))
> +
> +@cfu_twice@
> +position p != ok.p;
> +identifier src;
> +expression dest1, dest2, size1, size2, offset, e1, e2;
> +@@
> +
> +*copy_from_user(dest1, src, size1)
> + ... when != src = offset
> + when != src += offset
> + when != src -= offset
> + when != src ++
> + when != src --
> + when != if (size2 > e1 || ...) { ... return ...; }
> + when != if (size2 > e1 || ...) { ... size2 = e2 ... }
> +*copy_from_user@p(dest2, src, size2)
> +
> +@script:python depends on org@
> +p << cfu_twice.p;
> +@@
> +
> +cocci.print_main("potentially dangerous second copy_from_user()",p)
> +
> +@script:python depends on report@
> +p << cfu_twice.p;
> +@@
> +
> +coccilib.report.print_report(p[0],"potentially dangerous second copy_from_user()")
> diff --git a/scripts/coccinelle/tests/reusercopy-wang.cocci b/scripts/coccinelle/tests/reusercopy-wang.cocci
> new file mode 100644
> index 000000000000..f57a1d997882
> --- /dev/null
> +++ b/scripts/coccinelle/tests/reusercopy-wang.cocci
> @@ -0,0 +1,389 @@
> +/// Recopying from the same user buffer frequently indicates a pattern of
> +/// reading a size header, allocating, and then re-reading an entire
> +/// structure. If the structure's size is not re-validated, this can lead
> +/// to structure or data size confusions.
> +///
> +// Confidence: Moderate
> +// Copyright: (C) 2013 Kees Cook, Chromium.
> +// Copyright: (C) 2016 Pengfei Wang.
> +// License: GPLv2.
> +// URL: http://coccinelle.lip6.fr/
> +// Comments:
> +// Options: --no-includes --include-headers
> +
> +virtual report
> +virtual org
> +virtual context
> +
> +@initialize:python@
> +@@
> +# -------------------------Post Matching Process--------------------------
> +def post_match_process(rule,p1,p2,src,ptr):
> + filename = p1[0].file
> + first = int(p1[0].line)
> + second = int(p2[0].line)
> +
> + src_str = str(src)
> + ptr_str = str(ptr)
> +
> + # Remove loop case, first and second fetch are not supposed to be
> + # in the same line.
> + if first == second:
> + return
> +
> + # Remove reverse loop case, where first fetch behind second fetch
> + # but in last loop .
> + if first > second:
> + return
> +
> + # Remove false matching of src ===> (int*)src , but leave
> + # function call like u64_to_uptr(ctl_sccb.sccb)
> + if src_str.find("(") == 0 or ptr_str.find("(") == 0:
> + return
> +
> + coccilib.report.print_report(p2[0],
> + "potentially dangerous second copy_from_user() (rule %d: line %d vs line %d)" %
> + (rule, first, second))
> +
> +
> +//-----------------Pattern Matching Rules-----------------------------------
> +//------------------------------- case 1: normal case without src assignment
> +@ rule1 disable drop_cast exists @
> +expression addr,exp1,exp2,src,size1,size2,offset,e1,e2;
> +position p1,p2;
> +identifier func;
> +type T1,T2;
> +@@
> + func(...){
> + ...
> +(
> + copy_from_user(exp1, (T1)src, size1)@p1
> +|
> + copy_from_user(exp1, src, size1)@p1
> +|
> + __copy_from_user(exp1, (T1)src, size1)@p1
> +|
> + __copy_from_user(exp1, src, size1)@p1
> +
> +)
> + ... when any
> + when != src = addr
> + when != src ++
> + when != src --
> + when != src += offset
> + when != src -= offset
> + when != src = src + offset
> + when != src = src - offset
> + when != if (size2 > e1 || ...) { ... return ...; }
> + when != if (size2 > e1 || ...) { ... size2 = e2 ... }
> +
> +(
> + __copy_from_user(exp2,(T2)src,size2)@p2
> +|
> + __copy_from_user(exp2, src,size2)@p2
> +|
> + copy_from_user(exp2,(T2)src,size2)@p2
> +|
> + copy_from_user(exp2, src,size2)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p11 << rule1.p1;
> +p12 << rule1.p2;
> +s1 << rule1.src;
> +@@
> +
> +if p11 and p12:
> + post_match_process(1, p11, p12, s1, s1)
> +
> +//------------------------------ case 2: ptr = src at beginning, ptr first
> +@ rule2 disable drop_cast exists @
> +identifier func;
> +expression addr,exp1,exp2,src,ptr,size1,size2,offset,e1,e2;
> +position p0,p1,p2;
> +type T0,T1,T2;
> +@@
> +
> +
> + func(...){
> + ...
> +(
> + ptr = (T0)src@p0 // potential assignment case
> +|
> + ptr = src@p0
> +)
> + ...
> +(
> + copy_from_user(exp1, (T1)ptr,size1)@p1
> +|
> + copy_from_user(exp1, ptr,size1)@p1
> +|
> + __copy_from_user(exp1, (T1)ptr,size1)@p1
> +|
> + __copy_from_user(exp1, ptr,size1)@p1
> +)
> + ...
> + when != src = addr
> + when != src ++
> + when != src --
> + when != src += offset
> + when != src -= offset
> + when != src = src + offset
> + when != src = src - offset
> + when != if (size2 > e1 || ...) { ... return ...; }
> + when != if (size2 > e1 || ...) { ... size2 = e2 ... }
> +(
> + __copy_from_user(exp2,(T2)src,size2)@p2
> +|
> + __copy_from_user(exp2, src,size2)@p2
> +|
> + copy_from_user(exp2,(T2)src,size2)@p2
> +|
> + copy_from_user(exp2, src,size2)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p21 << rule2.p1;
> +p22 << rule2.p2;
> +p2 << rule2.ptr;
> +s2 << rule2.src;
> +@@
> +if p21 and p22:
> + post_match_process(2, p21, p22, s2, p2)
> +//------------------------- case 3: ptr = src at beginning, src first
> +@ rule3 disable drop_cast exists @
> +identifier func;
> +expression addr,exp1,exp2,src,ptr,size1,size2,offset,e1,e2;
> +position p0,p1,p2;
> +type T0,T1,T2;
> +@@
> +
> +
> + func(...){
> + ...
> +(
> + ptr = (T0)src@p0 // potential assignment case
> +|
> + ptr = src@p0
> +)
> + ...
> +(
> + copy_from_user(exp1, (T1)src,size1)@p1
> +|
> + copy_from_user(exp1, src,size1)@p1
> +|
> + __copy_from_user(exp1, (T1)src,size1)@p1
> +|
> + __copy_from_user(exp1, src,size1)@p1
> +)
> + ...
> + when != src = addr
> + when != src ++
> + when != src --
> + when != src += offset
> + when != src -= offset
> + when != src = src + offset
> + when != src = src - offset
> + when != if (size2 > e1 || ...) { ... return ...; }
> + when != if (size2 > e1 || ...) { ... size2 = e2 ... }
> +(
> + __copy_from_user(exp2,(T2)ptr,size2)@p2
> +|
> + __copy_from_user(exp2, ptr,size2)@p2
> +|
> + copy_from_user(exp2,(T2)ptr,size2)@p2
> +|
> + copy_from_user(exp2, ptr,size2)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p31 << rule3.p1;
> +p32 << rule3.p2;
> +p3 << rule3.ptr;
> +s3 << rule3.src;
> +@@
> +if p31 and p32:
> + post_match_process(3, p31, p32, s3, p3)
> +//----------------------------------- case 4: ptr = src at middle
> +
> +@ rule4 disable drop_cast exists @
> +identifier func;
> +expression addr,exp1,exp2,src,ptr,size1,size2,offset,e1,e2;
> +position p0,p1,p2;
> +type T0,T1,T2;
> +@@
> +
> +
> + func(...){
> + ...
> +(
> + copy_from_user(exp1, (T1)src,size1)@p1
> +|
> + copy_from_user(exp1, src,size1)@p1
> +|
> + __copy_from_user(exp1, (T1)src,size1)@p1
> +|
> + __copy_from_user(exp1, src,size1)@p1
> +)
> + ...
> + when != src = addr
> + when != src ++
> + when != src --
> + when != src += offset
> + when != src -= offset
> + when != src = src + offset
> + when != src = src - offset
> + when != if (size2 > e1 || ...) { ... return ...; }
> + when != if (size2 > e1 || ...) { ... size2 = e2 ... }
> +
> +(
> + ptr = (T0)src@p0 // potential assignment case
> +|
> + ptr = src@p0
> +)
> + ...
> + when != ptr = addr
> + when != ptr ++
> + when != ptr --
> + when != ptr += offset
> + when != ptr -= offset
> + when != ptr = ptr + offset
> + when != ptr = ptr - offset
> + when != if (size2 > e1 || ...) { ... return ...; }
> + when != if (size2 > e1 || ...) { ... size2 = e2 ... }
> +
> +(
> + __copy_from_user(exp2,(T2)ptr,size2)@p2
> +|
> + __copy_from_user(exp2, ptr,size2)@p2
> +|
> + copy_from_user(exp2,(T2)ptr,size2)@p2
> +|
> + copy_from_user(exp2, ptr,size2)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p41 << rule4.p1;
> +p42 << rule4.p2;
> +p4 << rule4.ptr;
> +s4 << rule4.src;
> +@@
> +if p41 and p42:
> + post_match_process(4, p41, p42, s4, p4)
> +
> +//-------------------- case 5: first element, then ptr, copy from structure
> +@ rule5 disable drop_cast exists @
> +identifier func, f1;
> +expression addr,exp1,exp2,src,size1,size2,offset,e1,e2;
> +position p1,p2;
> +type T1,T2;
> +@@
> +
> +
> + func(...){
> + ...
> +(
> + copy_from_user(exp1, (T1)src->f1,size1)@p1
> +|
> + copy_from_user(exp1, src->f1,size1)@p1
> +|
> + copy_from_user(exp1, &(src->f1),size1)@p1
> +|
> + __copy_from_user(exp1, (T1)src->f1,size1)@p1
> +|
> + __copy_from_user(exp1, src->f1,size1)@p1
> +|
> + __copy_from_user(exp1, &(src->f1),size1)@p1
> +)
> + ...
> + when != src = addr
> + when != src ++
> + when != src --
> + when != src += offset
> + when != src -= offset
> + when != src = src + offset
> + when != src = src - offset
> + when != if (size2 > e1 || ...) { ... return ...; }
> + when != if (size2 > e1 || ...) { ... size2 = e2 ... }
> +(
> + __copy_from_user(exp2,(T2)src,size2)@p2
> +|
> + __copy_from_user(exp2,src,size2)@p2
> +|
> + copy_from_user(exp2,(T2)src,size2)@p2
> +|
> + copy_from_user(exp2,src,size2)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p51 << rule5.p1;
> +p52 << rule5.p2;
> +s5 << rule5.src;
> +e5 << rule5.f1;
> +@@
> +if p51 and p52:
> + post_match_process(5, p51, p52, s5, e5)
> +
> +
> +//---------------------- case 6: first element, then ptr, copy from pointer
> +@ rule6 disable drop_cast exists @
> +identifier func, f1;
> +expression addr,exp1,exp2,src,size1,size2,offset,e1,e2;
> +position p1,p2;
> +type T1,T2;
> +@@
> + func(...){
> + ...
> +(
> + copy_from_user(exp1, (T1)src.f1, size1)@p1
> +|
> + copy_from_user(exp1, src.f1, size1)@p1
> +|
> + copy_from_user(exp1, &(src.f1), size1)@p1
> +|
> + __copy_from_user(exp1, (T1)src.f1, size1)@p1
> +|
> + __copy_from_user(exp1, src.f1, size1)@p1
> +|
> + __copy_from_user(exp1, &(src.f1), size1)@p1
> +)
> + ...
> + when != &src = addr
> + when != &src ++
> + when != &src --
> + when != &src += offset
> + when != &src -= offset
> + when != &src = &src + offset
> + when != &src = &src - offset
> + when != if (size2 > e1 || ...) { ... return ...; }
> + when != if (size2 > e1 || ...) { ... size2 = e2 ... }
> +(
> + __copy_from_user(exp2,(T2)&src,size2)@p2
> +|
> + __copy_from_user(exp2,&src,size2)@p2
> +|
> + copy_from_user(exp2,(T2)&src,size2)@p2
> +|
> + copy_from_user(exp2,&src,size2)@p2
> +)
> + ...
> + }
> +
> +@script:python depends on report@
> +p61 << rule6.p1;
> +p62 << rule6.p2;
> +s6 << rule6.src;
> +e6 << rule6.f1;
> +@@
> +if p61 and p62:
> + post_match_process(6, p61, p62, s6, e6)
> --
> 2.7.4
>
>
> --
> Kees Cook
> Nexus Security
>

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