The patch titled
Subject: kernel/sys.c:uname(): fix stack memory content leak via UNAME26
has been added to the -mm tree. Its filename is
kernel-sysc-fix-stack-memory-content-leak-via-uname26.patch
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------------------------------------------------------
From: Kees Cook <keescook@xxxxxxxxxxxx>
Subject: kernel/sys.c:uname(): fix stack memory content leak via UNAME26
Calling uname() with the UNAME26 personality set allows a leak of kernel
stack contents. This fixes it by initializing the stack buffer to zero,
defensively calculating the length of copy_to_user() call, and making the
len argument unsigned.
CVE-2012-0957
Reported-by: PaX Team <pageexec@xxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/sys.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff -puN kernel/sys.c~kernel-sysc-fix-stack-memory-content-leak-via-uname26 kernel/sys.c
--- a/kernel/sys.c~kernel-sysc-fix-stack-memory-content-leak-via-uname26
+++ a/kernel/sys.c
@@ -1265,13 +1265,13 @@ DECLARE_RWSEM(uts_sem);
* Work around broken programs that cannot handle "Linux 3.0".
* Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40
*/
-static int override_release(char __user *release, int len)
+static int override_release(char __user *release, size_t len)
{
int ret = 0;
- char buf[65];
if (current->personality & UNAME26) {
- char *rest = UTS_RELEASE;
+ const char *rest = UTS_RELEASE;
+ char buf[65] = { 0 };
int ndots = 0;
unsigned v;
@@ -1283,7 +1283,9 @@ static int override_release(char __user
rest++;
}
v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40;
- snprintf(buf, len, "2.6.%u%s", v, rest);
+ snprintf(buf, sizeof(buf), "2.6.%u%s", v, rest);
+ if (sizeof(buf) < len)
+ len = sizeof(buf);
ret = copy_to_user(release, buf, len);
}
return ret;
_
Patches currently in -mm which might be from keescook@xxxxxxxxxxxx are
origin.patch
linux-next.patch
kernel-sysc-fix-stack-memory-content-leak-via-uname26.patch
proc-dont-show-nonexistent-capabilities.patch
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