[PATCH 1/2] remove all uses of printf's %n

From: Kees Cook
Date: Mon Sep 16 2013 - 03:46:06 EST


All users of %n are calculating padding size when using seq_file, so
instead use the new last_len member for discovering the length of the
written strings.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
fs/proc/consoles.c | 5 +++--
fs/proc/nommu.c | 6 ++++--
fs/proc/task_mmu.c | 6 ++++--
fs/proc/task_nommu.c | 6 ++++--
net/ipv4/fib_trie.c | 10 ++++++----
net/ipv4/ping.c | 10 ++++++----
net/ipv4/tcp_ipv4.c | 28 ++++++++++++++--------------
net/ipv4/udp.c | 10 ++++++----
net/phonet/socket.c | 18 +++++++++++-------
net/sctp/objcnt.c | 6 ++++--
10 files changed, 62 insertions(+), 43 deletions(-)

diff --git a/fs/proc/consoles.c b/fs/proc/consoles.c
index b701eaa..08cd2ee 100644
--- a/fs/proc/consoles.c
+++ b/fs/proc/consoles.c
@@ -47,8 +47,9 @@ static int show_console_dev(struct seq_file *m, void *v)
con_flags[a].name : ' ';
flags[a] = 0;

- seq_printf(m, "%s%d%n", con->name, con->index, &len);
- len = 21 - len;
+ len = m->count;
+ seq_printf(m, "%s%d", con->name, con->index);
+ len = 21 - (m->count - len);
if (len < 1)
len = 1;
seq_printf(m, "%*c%c%c%c (%s)", len, ' ', con->read ? 'R' : '-',
diff --git a/fs/proc/nommu.c b/fs/proc/nommu.c
index ccfd99b..db0700d 100644
--- a/fs/proc/nommu.c
+++ b/fs/proc/nommu.c
@@ -50,8 +50,9 @@ static int nommu_region_show(struct seq_file *m, struct vm_region *region)
ino = inode->i_ino;
}

+ len = m->count;
seq_printf(m,
- "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
+ "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
region->vm_start,
region->vm_end,
flags & VM_READ ? 'r' : '-',
@@ -59,7 +60,8 @@ static int nommu_region_show(struct seq_file *m, struct vm_region *region)
flags & VM_EXEC ? 'x' : '-',
flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
((loff_t)region->vm_pgoff) << PAGE_SHIFT,
- MAJOR(dev), MINOR(dev), ino, &len);
+ MAJOR(dev), MINOR(dev), ino);
+ len = m->count - len;

if (file) {
len = 25 + sizeof(void *) * 6 - len;
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 7366e9d..eaca69c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -286,7 +286,8 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
if (stack_guard_page_end(vma, end))
end -= PAGE_SIZE;

- seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
+ len = m->count;
+ seq_printf(m, "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
start,
end,
flags & VM_READ ? 'r' : '-',
@@ -294,7 +295,8 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma, int is_pid)
flags & VM_EXEC ? 'x' : '-',
flags & VM_MAYSHARE ? 's' : 'p',
pgoff,
- MAJOR(dev), MINOR(dev), ino, &len);
+ MAJOR(dev), MINOR(dev), ino);
+ len = m->count - len;

/*
* Print the dentry name for named mappings, and a
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 56123a6..04c8246 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -155,8 +155,9 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
}

+ len = m->count;
seq_printf(m,
- "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu %n",
+ "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
vma->vm_start,
vma->vm_end,
flags & VM_READ ? 'r' : '-',
@@ -164,7 +165,8 @@ static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma,
flags & VM_EXEC ? 'x' : '-',
flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
pgoff,
- MAJOR(dev), MINOR(dev), ino, &len);
+ MAJOR(dev), MINOR(dev), ino);
+ len = m->count - len;

if (file) {
pad_len_spaces(m, len);
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 3df6d3e..9537a95 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -2536,10 +2536,11 @@ static int fib_route_seq_show(struct seq_file *seq, void *v)
|| fa->fa_type == RTN_MULTICAST)
continue;

+ len = seq->count;
if (fi)
seq_printf(seq,
"%s\t%08X\t%08X\t%04X\t%d\t%u\t"
- "%d\t%08X\t%d\t%u\t%u%n",
+ "%d\t%08X\t%d\t%u\t%u",
fi->fib_dev ? fi->fib_dev->name : "*",
prefix,
fi->fib_nh->nh_gw, flags, 0, 0,
@@ -2548,13 +2549,14 @@ static int fib_route_seq_show(struct seq_file *seq, void *v)
(fi->fib_advmss ?
fi->fib_advmss + 40 : 0),
fi->fib_window,
- fi->fib_rtt >> 3, &len);
+ fi->fib_rtt >> 3);
else
seq_printf(seq,
"*\t%08X\t%08X\t%04X\t%d\t%u\t"
- "%d\t%08X\t%d\t%u\t%u%n",
+ "%d\t%08X\t%d\t%u\t%u",
prefix, 0, flags, 0, 0, 0,
- mask, 0, 0, 0, &len);
+ mask, 0, 0, 0);
+ len = seq->count - len;

seq_printf(seq, "%*s\n", 127 - len, "");
}
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index d7d9882..c87d062 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -1073,7 +1073,7 @@ void ping_seq_stop(struct seq_file *seq, void *v)
EXPORT_SYMBOL_GPL(ping_seq_stop);

static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
- int bucket, int *len)
+ int bucket)
{
struct inet_sock *inet = inet_sk(sp);
__be32 dest = inet->inet_daddr;
@@ -1082,7 +1082,7 @@ static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
__u16 srcp = ntohs(inet->inet_sport);

seq_printf(f, "%5d: %08X:%04X %08X:%04X"
- " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d%n",
+ " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
bucket, src, srcp, dest, destp, sp->sk_state,
sk_wmem_alloc_get(sp),
sk_rmem_alloc_get(sp),
@@ -1090,7 +1090,7 @@ static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
0, sock_i_ino(sp),
atomic_read(&sp->sk_refcnt), sp,
- atomic_read(&sp->sk_drops), len);
+ atomic_read(&sp->sk_drops));
}

static int ping_v4_seq_show(struct seq_file *seq, void *v)
@@ -1104,7 +1104,9 @@ static int ping_v4_seq_show(struct seq_file *seq, void *v)
struct ping_iter_state *state = seq->private;
int len;

- ping_v4_format_sock(v, seq, state->bucket, &len);
+ len = seq->count;
+ ping_v4_format_sock(v, seq, state->bucket);
+ len = seq->count - len;
seq_printf(seq, "%*s\n", 127 - len, "");
}
return 0;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index b14266b..cdded47 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2598,13 +2598,13 @@ void tcp_proc_unregister(struct net *net, struct tcp_seq_afinfo *afinfo)
EXPORT_SYMBOL(tcp_proc_unregister);

static void get_openreq4(const struct sock *sk, const struct request_sock *req,
- struct seq_file *f, int i, kuid_t uid, int *len)
+ struct seq_file *f, int i, kuid_t uid)
{
const struct inet_request_sock *ireq = inet_rsk(req);
long delta = req->expires - jiffies;

seq_printf(f, "%4d: %08X:%04X %08X:%04X"
- " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK%n",
+ " %02X %08X:%08X %02X:%08lX %08X %5u %8d %u %d %pK",
i,
ireq->loc_addr,
ntohs(inet_sk(sk)->inet_sport),
@@ -2619,11 +2619,10 @@ static void get_openreq4(const struct sock *sk, const struct request_sock *req,
0, /* non standard timer */
0, /* open_requests have no inode */
atomic_read(&sk->sk_refcnt),
- req,
- len);
+ req);
}

-static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
+static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
{
int timer_active;
unsigned long timer_expires;
@@ -2662,7 +2661,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);

seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
- "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d%n",
+ "%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
i, src, srcp, dest, destp, sk->sk_state,
tp->write_seq - tp->snd_una,
rx_queue,
@@ -2679,12 +2678,11 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
tp->snd_cwnd,
sk->sk_state == TCP_LISTEN ?
(fastopenq ? fastopenq->max_qlen : 0) :
- (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh),
- len);
+ (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh));
}

static void get_timewait4_sock(const struct inet_timewait_sock *tw,
- struct seq_file *f, int i, int *len)
+ struct seq_file *f, int i)
{
__be32 dest, src;
__u16 destp, srcp;
@@ -2696,10 +2694,10 @@ static void get_timewait4_sock(const struct inet_timewait_sock *tw,
srcp = ntohs(tw->tw_sport);

seq_printf(f, "%4d: %08X:%04X %08X:%04X"
- " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
+ " %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
- atomic_read(&tw->tw_refcnt), tw, len);
+ atomic_read(&tw->tw_refcnt), tw);
}

#define TMPSZ 150
@@ -2718,18 +2716,20 @@ static int tcp4_seq_show(struct seq_file *seq, void *v)
}
st = seq->private;

+ len = seq->count;
switch (st->state) {
case TCP_SEQ_STATE_LISTENING:
case TCP_SEQ_STATE_ESTABLISHED:
- get_tcp4_sock(v, seq, st->num, &len);
+ get_tcp4_sock(v, seq, st->num);
break;
case TCP_SEQ_STATE_OPENREQ:
- get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid, &len);
+ get_openreq4(st->syn_wait_sk, v, seq, st->num, st->uid);
break;
case TCP_SEQ_STATE_TIME_WAIT:
- get_timewait4_sock(v, seq, st->num, &len);
+ get_timewait4_sock(v, seq, st->num);
break;
}
+ len = seq->count - len;
seq_printf(seq, "%*s\n", TMPSZ - 1 - len, "");
out:
return 0;
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 74d2c95..5460ab9 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2150,7 +2150,7 @@ EXPORT_SYMBOL(udp_proc_unregister);

/* ------------------------------------------------------------------------ */
static void udp4_format_sock(struct sock *sp, struct seq_file *f,
- int bucket, int *len)
+ int bucket)
{
struct inet_sock *inet = inet_sk(sp);
__be32 dest = inet->inet_daddr;
@@ -2159,7 +2159,7 @@ static void udp4_format_sock(struct sock *sp, struct seq_file *f,
__u16 srcp = ntohs(inet->inet_sport);

seq_printf(f, "%5d: %08X:%04X %08X:%04X"
- " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d%n",
+ " %02X %08X:%08X %02X:%08lX %08X %5u %8d %lu %d %pK %d",
bucket, src, srcp, dest, destp, sp->sk_state,
sk_wmem_alloc_get(sp),
sk_rmem_alloc_get(sp),
@@ -2167,7 +2167,7 @@ static void udp4_format_sock(struct sock *sp, struct seq_file *f,
from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
0, sock_i_ino(sp),
atomic_read(&sp->sk_refcnt), sp,
- atomic_read(&sp->sk_drops), len);
+ atomic_read(&sp->sk_drops));
}

int udp4_seq_show(struct seq_file *seq, void *v)
@@ -2181,7 +2181,9 @@ int udp4_seq_show(struct seq_file *seq, void *v)
struct udp_iter_state *state = seq->private;
int len;

- udp4_format_sock(v, seq, state->bucket, &len);
+ len = seq->count;
+ udp4_format_sock(v, seq, state->bucket);
+ len = seq->count - len;
seq_printf(seq, "%*s\n", 127 - len, "");
}
return 0;
diff --git a/net/phonet/socket.c b/net/phonet/socket.c
index 77e38f7..b8712ad 100644
--- a/net/phonet/socket.c
+++ b/net/phonet/socket.c
@@ -597,23 +597,25 @@ static int pn_sock_seq_show(struct seq_file *seq, void *v)
{
int len;

+ len = seq->count;
if (v == SEQ_START_TOKEN)
- seq_printf(seq, "%s%n", "pt loc rem rs st tx_queue rx_queue "
- " uid inode ref pointer drops", &len);
+ seq_puts(seq, "pt loc rem rs st tx_queue rx_queue "
+ " uid inode ref pointer drops");
else {
struct sock *sk = v;
struct pn_sock *pn = pn_sk(sk);

seq_printf(seq, "%2d %04X:%04X:%02X %02X %08X:%08X %5d %lu "
- "%d %pK %d%n",
+ "%d %pK %d",
sk->sk_protocol, pn->sobject, pn->dobject,
pn->resource, sk->sk_state,
sk_wmem_alloc_get(sk), sk_rmem_alloc_get(sk),
from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)),
sock_i_ino(sk),
atomic_read(&sk->sk_refcnt), sk,
- atomic_read(&sk->sk_drops), &len);
+ atomic_read(&sk->sk_drops));
}
+ len = seq->count - len;
seq_printf(seq, "%*s\n", 127 - len, "");
return 0;
}
@@ -787,17 +789,19 @@ static int pn_res_seq_show(struct seq_file *seq, void *v)
{
int len;

+ len = seq->count;
if (v == SEQ_START_TOKEN)
- seq_printf(seq, "%s%n", "rs uid inode", &len);
+ seq_puts(seq, "rs uid inode");
else {
struct sock **psk = v;
struct sock *sk = *psk;

- seq_printf(seq, "%02X %5u %lu%n",
+ seq_printf(seq, "%02X %5u %lu",
(int) (psk - pnres.sk),
from_kuid_munged(seq_user_ns(seq), sock_i_uid(sk)),
- sock_i_ino(sk), &len);
+ sock_i_ino(sk));
}
+ len = seq->count - len;
seq_printf(seq, "%*s\n", 63 - len, "");
return 0;
}
diff --git a/net/sctp/objcnt.c b/net/sctp/objcnt.c
index 5ea573b..b3f4a3c 100644
--- a/net/sctp/objcnt.c
+++ b/net/sctp/objcnt.c
@@ -82,8 +82,10 @@ static int sctp_objcnt_seq_show(struct seq_file *seq, void *v)
int i, len;

i = (int)*(loff_t *)v;
- seq_printf(seq, "%s: %d%n", sctp_dbg_objcnt[i].label,
- atomic_read(sctp_dbg_objcnt[i].counter), &len);
+ len = seq->count;
+ seq_printf(seq, "%s: %d", sctp_dbg_objcnt[i].label,
+ atomic_read(sctp_dbg_objcnt[i].counter));
+ len = seq->count - len;
seq_printf(seq, "%*s\n", 127 - len, "");
return 0;
}
--
1.7.9.5

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