diff --git a/debian/changelog b/debian/changelog index 61885a21f..28f0c67ec 100644 --- a/debian/changelog +++ b/debian/changelog @@ -96,6 +96,7 @@ linux (3.2.32-1) UNRELEASED; urgency=low * [x86] storvsc: Account for in-transit packets in the RESET path * fs: handle failed audit_log_start properly * fs: prevent use after free in auditing when symlink following was denied + * kernel/sys.c: fix stack memory content leak via UNAME26 (CVE-2012-0957) -- Ben Hutchings Sat, 29 Sep 2012 14:19:46 +0200 diff --git a/debian/patches/bugfix/all/kernel-sys.c-fix-stack-memory-content-leak-via-UNAME.patch b/debian/patches/bugfix/all/kernel-sys.c-fix-stack-memory-content-leak-via-UNAME.patch new file mode 100644 index 000000000..a8a86de0c --- /dev/null +++ b/debian/patches/bugfix/all/kernel-sys.c-fix-stack-memory-content-leak-via-UNAME.patch @@ -0,0 +1,60 @@ +From: Kees Cook +Date: Fri, 19 Oct 2012 13:56:51 -0700 +Subject: [1/2] kernel/sys.c: fix stack memory content leak via UNAME26 + +commit 2702b1526c7278c4d65d78de209a465d4de2885e upstream. + +Calling uname() with the UNAME26 personality set allows a leak of kernel +stack contents. This fixes it by defensively calculating the length of +copy_to_user() call, making the len argument unsigned, and initializing +the stack buffer to zero (now technically unneeded, but hey, overkill). + +CVE-2012-0957 + +Reported-by: PaX Team +Signed-off-by: Kees Cook +Cc: Andi Kleen +Cc: PaX Team +Cc: Brad Spengler +Signed-off-by: Andrew Morton +Signed-off-by: Linus Torvalds +--- + kernel/sys.c | 12 +++++++----- + 1 file changed, 7 insertions(+), 5 deletions(-) + +diff --git a/kernel/sys.c b/kernel/sys.c +index c5cb5b9..01865c6 100644 +--- a/kernel/sys.c ++++ b/kernel/sys.c +@@ -1265,15 +1265,16 @@ 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; ++ size_t copy; + + while (*rest) { + if (*rest == '.' && ++ndots >= 3) +@@ -1283,8 +1284,9 @@ static int override_release(char __user *release, int len) + rest++; + } + v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40; +- snprintf(buf, len, "2.6.%u%s", v, rest); +- ret = copy_to_user(release, buf, len); ++ copy = min(sizeof(buf), max_t(size_t, 1, len)); ++ copy = scnprintf(buf, copy, "2.6.%u%s", v, rest); ++ ret = copy_to_user(release, buf, copy + 1); + } + return ret; + } diff --git a/debian/patches/bugfix/all/use-clamp_t-in-UNAME26-fix.patch b/debian/patches/bugfix/all/use-clamp_t-in-UNAME26-fix.patch new file mode 100644 index 000000000..0f60973f9 --- /dev/null +++ b/debian/patches/bugfix/all/use-clamp_t-in-UNAME26-fix.patch @@ -0,0 +1,32 @@ +From: Kees Cook +Date: Fri, 19 Oct 2012 18:45:53 -0700 +Subject: [2/2] use clamp_t in UNAME26 fix + +commit 31fd84b95eb211d5db460a1dda85e004800a7b52 upstream. + +The min/max call needed to have explicit types on some architectures +(e.g. mn10300). Use clamp_t instead to avoid the warning: + + kernel/sys.c: In function 'override_release': + kernel/sys.c:1287:10: warning: comparison of distinct pointer types lacks a cast [enabled by default] + +Reported-by: Fengguang Wu +Signed-off-by: Kees Cook +Signed-off-by: Linus Torvalds +--- + kernel/sys.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/kernel/sys.c b/kernel/sys.c +index 01865c6..e6e0ece 100644 +--- a/kernel/sys.c ++++ b/kernel/sys.c +@@ -1284,7 +1284,7 @@ static int override_release(char __user *release, size_t len) + rest++; + } + v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 40; +- copy = min(sizeof(buf), max_t(size_t, 1, len)); ++ copy = clamp_t(size_t, len, 1, sizeof(buf)); + copy = scnprintf(buf, copy, "2.6.%u%s", v, rest); + ret = copy_to_user(release, buf, copy + 1); + } diff --git a/debian/patches/series b/debian/patches/series index 196e98192..7a782d407 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -404,3 +404,5 @@ debian/iwlwifi-do-not-request-unreleased-firmware.patch debian/hid-avoid-ABI-change-in-3.2.31.patch debian/xfrm-avoid-ABI-change-in-3.2.31.patch bugfix/x86/SCSI-storvsc-Account-for-in-transit-packets-in-the-R.patch +bugfix/all/kernel-sys.c-fix-stack-memory-content-leak-via-UNAME.patch +bugfix/all/use-clamp_t-in-UNAME26-fix.patch