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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2013-09-30 13:45:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-30 14:31:02 -0700
commit4c1c7be95c345cf2ad537a0c48e9aeadc7304527 (patch)
treed60639057e1d30c853330c513754d8e43f7306cb
parentipc/sem.c: synchronize the proc interface (diff)
downloadlinux-dev-4c1c7be95c345cf2ad537a0c48e9aeadc7304527.tar.xz
linux-dev-4c1c7be95c345cf2ad537a0c48e9aeadc7304527.zip
kernel/kmod.c: check for NULL in call_usermodehelper_exec()
If /proc/sys/kernel/core_pattern contains only "|", a NULL pointer dereference happens upon core dump because argv_split("") returns argv[0] == NULL. This bug was once fixed by commit 264b83c07a84 ("usermodehelper: check subprocess_info->path != NULL") but was by error reintroduced by commit 7f57cfa4e2aa ("usermodehelper: kill the sub_info->path[0] check"). This bug seems to exist since 2.6.19 (the version which core dump to pipe was added). Depending on kernel version and config, some side effect might happen immediately after this oops (e.g. kernel panic with 2.6.32-358.18.1.el6). Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/kmod.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/kmod.c b/kernel/kmod.c
index fb326365b694..b086006c59e7 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -571,6 +571,10 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
DECLARE_COMPLETION_ONSTACK(done);
int retval = 0;
+ if (!sub_info->path) {
+ call_usermodehelper_freeinfo(sub_info);
+ return -EINVAL;
+ }
helper_lock();
if (!khelper_wq || usermodehelper_disabled) {
retval = -EBUSY;