[PATCH -next] hugetlbfs: a terminator for hugetlb_param_specs[]

From: Qian Cai
Date: Mon Feb 04 2019 - 20:22:46 EST


Booting up an arm64 server with CONFIG_VALIDATE_FS_PARSER=n triggers a
out-of-bounds error below, due to the commit 2284cf59cbce ("hugetlbfs:
Convert to fs_context") missed a terminator for hugetlb_param_specs[],
and causes this loop in fs_lookup_key(),

for (p = desc->specs; p->name; p++)

could not exit properly due to p->name is never be NULL.

[ 91.575203] BUG: KASAN: global-out-of-bounds in fs_lookup_key+0x60/0x94
[ 91.581810] Read of size 8 at addr ffff200010deeb10 by task mount/2461
[ 91.597350] Call trace:
[ 91.597357] dump_backtrace+0x0/0x2b0
[ 91.597361] show_stack+0x24/0x30
[ 91.597373] dump_stack+0xc0/0xf8
[ 91.623263] print_address_description+0x64/0x2b0
[ 91.627965] kasan_report+0x150/0x1a4
[ 91.627970] __asan_report_load8_noabort+0x30/0x3c
[ 91.627974] fs_lookup_key+0x60/0x94
[ 91.627977] fs_parse+0x104/0x990
[ 91.627986] hugetlbfs_parse_param+0xc4/0x5e8
[ 91.651081] vfs_parse_fs_param+0x2e4/0x378
[ 91.658118] vfs_parse_fs_string+0xbc/0x12c
[ 91.658122] do_mount+0x11f0/0x1640
[ 91.658125] ksys_mount+0xc0/0xd0
[ 91.658129] __arm64_sys_mount+0xcc/0xe4
[ 91.658137] el0_svc_handler+0x28c/0x338
[ 91.681740] el0_svc+0x8/0xc

Fixes: 2284cf59cbce ("hugetlbfs: Convert to fs_context")
Signed-off-by: Qian Cai <cai@xxxxxx>
---
fs/hugetlbfs/inode.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index abf0c2eb834e..4f352743930f 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -81,6 +81,7 @@ static const struct fs_parameter_spec hugetlb_param_specs[] = {
fsparam_string("pagesize", Opt_pagesize),
fsparam_string("size", Opt_size),
fsparam_u32 ("uid", Opt_uid),
+ {}
};

static const struct fs_parameter_description hugetlb_fs_parameters = {
--
2.17.2 (Apple Git-113)