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authorAmanieu d'Antras <amanieu@gmail.com>2015-08-06 15:46:33 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-08-16 20:52:25 -0700
commit8a97f0e58abc93f67f1f6ca571e4ff758739cedf (patch)
parent7f488aad4f9dbaced8a4529817a7404658406a96 (diff)
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/signalfd.c b/fs/signalfd.c
index 7e412ad74836..270221fcef42 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,