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Subject[PATCH] af_unix: Add sockaddr length checks before accessing sa_family in bind and connect handlers
Date
Verify that the caller-provided sockaddr structure is large enough to
contain the sa_family field, before accessing it in bind() and connect()
handlers of the AF_UNIX socket. Since neither syscall enforces a minimum
size of the corresponding memory region, very short sockaddrs (zero or
one byte long) result in operating on uninitialized memory while
referencing .sa_family.

Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com>
---
net/unix/af_unix.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 6a7fe7660551..1a0c961f4ffe 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -999,7 +999,8 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
struct path path = { };

err = -EINVAL;
- if (sunaddr->sun_family != AF_UNIX)
+ if (addr_len < offsetofend(struct sockaddr_un, sun_family) ||
+ sunaddr->sun_family != AF_UNIX)
goto out;

if (addr_len == sizeof(short)) {
@@ -1110,6 +1111,10 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
unsigned int hash;
int err;

+ err = -EINVAL;
+ if (alen < offsetofend(struct sockaddr, sa_family))
+ goto out;
+
if (addr->sa_family != AF_UNSPEC) {
err = unix_mkname(sunaddr, alen, &hash);
if (err < 0)
--
2.13.1.508.gb3defc5cc-goog
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