--- /dev/null
+From 3c00cb5e68dc719f2fc73a33b1b230aadfcb1309 Mon Sep 17 00:00:00 2001
+From: Amanieu d'Antras <amanieu@gmail.com>
+Date: Thu, 6 Aug 2015 15:46:26 -0700
+Subject: signal: fix information leak in copy_siginfo_from_user32
+
+From: Amanieu d'Antras <amanieu@gmail.com>
+
+commit 3c00cb5e68dc719f2fc73a33b1b230aadfcb1309 upstream.
+
+This function can leak kernel stack data when the user siginfo_t has a
+positive si_code value. The top 16 bits of si_code descibe which fields
+in the siginfo_t union are active, but they are treated inconsistently
+between copy_siginfo_from_user32, copy_siginfo_to_user32 and
+copy_siginfo_to_user.
+
+copy_siginfo_from_user32 is called from rt_sigqueueinfo and
+rt_tgsigqueueinfo in which the user has full control overthe top 16 bits
+of si_code.
+
+This fixes the following information leaks:
+x86: 8 bytes leaked when sending a signal from a 32-bit process to
+ itself. This leak grows to 16 bytes if the process uses x32.
+ (si_code = __SI_CHLD)
+x86: 100 bytes leaked when sending a signal from a 32-bit process to
+ a 64-bit process. (si_code = -1)
+sparc: 4 bytes leaked when sending a signal from a 32-bit process to a
+ 64-bit process. (si_code = any)
+
+parsic and s390 have similar bugs, but they are not vulnerable because
+rt_[tg]sigqueueinfo have checks that prevent sending a positive si_code
+to a different process. These bugs are also fixed for consistency.
+
+Signed-off-by: Amanieu d'Antras <amanieu@gmail.com>
+Cc: Oleg Nesterov <oleg@redhat.com>
+Cc: Ingo Molnar <mingo@kernel.org>
+Cc: Russell King <rmk@arm.linux.org.uk>
+Cc: Ralf Baechle <ralf@linux-mips.org>
+Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
+Cc: Chris Metcalf <cmetcalf@ezchip.com>
+Cc: Paul Mackerras <paulus@samba.org>
+Cc: Michael Ellerman <mpe@ellerman.id.au>
+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>
+
+---
+ arch/arm64/kernel/signal32.c | 2 --
+ arch/mips/kernel/signal32.c | 2 --
+ arch/powerpc/kernel/signal_32.c | 2 --
+ arch/tile/kernel/compat_signal.c | 2 --
+ kernel/signal.c | 4 ++--
+ 5 files changed, 2 insertions(+), 10 deletions(-)
+
+--- a/arch/arm64/kernel/signal32.c
++++ b/arch/arm64/kernel/signal32.c
+@@ -202,8 +202,6 @@ int copy_siginfo_to_user32(compat_siginf
+
+ int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
+ {
+- memset(to, 0, sizeof *to);
+-
+ if (copy_from_user(to, from, __ARCH_SI_PREAMBLE_SIZE) ||
+ copy_from_user(to->_sifields._pad,
+ from->_sifields._pad, SI_PAD_SIZE))
+--- a/arch/mips/kernel/signal32.c
++++ b/arch/mips/kernel/signal32.c
+@@ -409,8 +409,6 @@ int copy_siginfo_to_user32(compat_siginf
+
+ int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
+ {
+- memset(to, 0, sizeof *to);
+-
+ if (copy_from_user(to, from, 3*sizeof(int)) ||
+ copy_from_user(to->_sifields._pad,
+ from->_sifields._pad, SI_PAD_SIZE32))
+--- a/arch/powerpc/kernel/signal_32.c
++++ b/arch/powerpc/kernel/signal_32.c
+@@ -966,8 +966,6 @@ int copy_siginfo_to_user32(struct compat
+
+ int copy_siginfo_from_user32(siginfo_t *to, struct compat_siginfo __user *from)
+ {
+- memset(to, 0, sizeof *to);
+-
+ if (copy_from_user(to, from, 3*sizeof(int)) ||
+ copy_from_user(to->_sifields._pad,
+ from->_sifields._pad, SI_PAD_SIZE32))
+--- a/arch/tile/kernel/compat_signal.c
++++ b/arch/tile/kernel/compat_signal.c
+@@ -113,8 +113,6 @@ int copy_siginfo_from_user32(siginfo_t *
+ if (!access_ok(VERIFY_READ, from, sizeof(struct compat_siginfo)))
+ return -EFAULT;
+
+- memset(to, 0, sizeof(*to));
+-
+ err = __get_user(to->si_signo, &from->si_signo);
+ err |= __get_user(to->si_errno, &from->si_errno);
+ err |= __get_user(to->si_code, &from->si_code);
+--- a/kernel/signal.c
++++ b/kernel/signal.c
+@@ -3025,7 +3025,7 @@ COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
+ int, sig,
+ struct compat_siginfo __user *, uinfo)
+ {
+- siginfo_t info;
++ siginfo_t info = {};
+ int ret = copy_siginfo_from_user32(&info, uinfo);
+ if (unlikely(ret))
+ return ret;
+@@ -3069,7 +3069,7 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo
+ int, sig,
+ struct compat_siginfo __user *, uinfo)
+ {
+- siginfo_t info;
++ siginfo_t info = {};
+
+ if (copy_siginfo_from_user32(&info, uinfo))
+ return -EFAULT;
--- /dev/null
+From 26135022f85105ad725cda103fa069e29e83bd16 Mon Sep 17 00:00:00 2001
+From: Amanieu d'Antras <amanieu@gmail.com>
+Date: Thu, 6 Aug 2015 15:46:29 -0700
+Subject: signal: fix information leak in copy_siginfo_to_user
+
+From: Amanieu d'Antras <amanieu@gmail.com>
+
+commit 26135022f85105ad725cda103fa069e29e83bd16 upstream.
+
+This function may copy the si_addr_lsb, si_lower and si_upper fields to
+user mode when they haven'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>
+Cc: Russell King <rmk@arm.linux.org.uk>
+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>
+
+---
+ arch/arm64/kernel/signal32.c | 3 ++-
+ kernel/signal.c | 9 ++++++---
+ 2 files changed, 8 insertions(+), 4 deletions(-)
+
+--- a/arch/arm64/kernel/signal32.c
++++ b/arch/arm64/kernel/signal32.c
+@@ -168,7 +168,8 @@ int copy_siginfo_to_user32(compat_siginf
+ * Other callers might not initialize the si_lsb field,
+ * so check explicitely for the right codes here.
+ */
+- if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
++ if (from->si_signo == SIGBUS &&
++ (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO))
+ err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
+ #endif
+ break;
+--- a/kernel/signal.c
++++ b/kernel/signal.c
+@@ -2753,12 +2753,15 @@ int copy_siginfo_to_user(siginfo_t __use
+ * Other callers might not initialize the si_lsb field,
+ * so check explicitly for the right codes here.
+ */
+- if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
++ if (from->si_signo == SIGBUS &&
++ (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO))
+ err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
+ #endif
+ #ifdef SEGV_BNDERR
+- err |= __put_user(from->si_lower, &to->si_lower);
+- err |= __put_user(from->si_upper, &to->si_upper);
++ if (from->si_signo == SIGSEGV && from->si_code == SEGV_BNDERR) {
++ err |= __put_user(from->si_lower, &to->si_lower);
++ err |= __put_user(from->si_upper, &to->si_upper);
++ }
+ #endif
+ break;
+ case __SI_CHLD:
--- /dev/null
+From 3ead7c52bdb0ab44f4bb1feed505a8323cc12ba7 Mon Sep 17 00:00:00 2001
+From: Amanieu d'Antras <amanieu@gmail.com>
+Date: Thu, 6 Aug 2015 15:46:33 -0700
+Subject: signalfd: fix information leak in signalfd_copyinfo
+
+From: Amanieu d'Antras <amanieu@gmail.com>
+
+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>
+
+---
+ fs/signalfd.c | 5 +++--
+ 1 file changed, 3 insertions(+), 2 deletions(-)
+
+--- a/fs/signalfd.c
++++ b/fs/signalfd.c
+@@ -121,8 +121,9 @@ static int signalfd_copyinfo(struct sign
+ * 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
projects / thirdparty / kernel / stable-queue.git / commitdiff
