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| author | Amanieu d'Antras <amanieu@gmail.com> | 2015-08-06 15:46:33 -0700 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-08-25 16:57:02 +0200 |
| commit | ce624e9ce4ef6efa702698ba52e793a84f96d606 (patch) | |
| tree | a3bc4fa6daf3e65b741a0a467a31f4dfbc5db389 | |
| parent | 6afc9ab280ef4a201ad352909c474a52ca1918f8 (diff) | |
| download | lwn-ce624e9ce4ef6efa702698ba52e793a84f96d606.tar.gz lwn-ce624e9ce4ef6efa702698ba52e793a84f96d606.zip | |
signalfd: fix information leak in signalfd_copyinfo
commit 3ead7c52bdb0ab44f4bb1feed505a8323cc12ba7 upstream.
This function may copy the si_addr_lsb field to user mode when it hasn't
been initialized, which can leak kernel stack data to user mode.
Just checking the value of si_code is insufficient because the same
si_code value is shared between multiple signals. This is solved by
checking the value of si_signo in addition to si_code.
Signed-off-by: Amanieu d'Antras <amanieu@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | fs/signalfd.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/signalfd.c b/fs/signalfd.c index 424b7b65321f..148f8e7af882 100644 --- a/fs/signalfd.c +++ b/fs/signalfd.c @@ -121,8 +121,9 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo, * Other callers might not initialize the si_lsb field, * so check explicitly for the right codes here. */ - if (kinfo->si_code == BUS_MCEERR_AR || - kinfo->si_code == BUS_MCEERR_AO) + if (kinfo->si_signo == SIGBUS && + (kinfo->si_code == BUS_MCEERR_AR || + kinfo->si_code == BUS_MCEERR_AO)) err |= __put_user((short) kinfo->si_addr_lsb, &uinfo->ssi_addr_lsb); #endif |