When msg is NULL, msg->msg_controllen exists to dereference a null pointer in recvmsg. The commit ae388becb529428ac926da102f1d025b3c3968da introduces this problem Signed-off-by: Qing Wu <wuqing30@huawei.com> Signed-off-by: Yan Zhu <zhuyan34@huawei.com> --- src/network/recvmsg.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/network/recvmsg.c b/src/network/recvmsg.c index 03641625..c36ffb8d 100644 --- a/src/network/recvmsg.c +++ b/src/network/recvmsg.c @@ -4,6 +4,7 @@ #include <sys/time.h> #include <string.h> #include "syscall.h" +#include <errno.h> hidden void __convert_scm_timestamps(struct msghdr *, socklen_t); @@ -49,6 +50,8 @@ void __convert_scm_timestamps(struct msghdr *msg, socklen_t csize) ssize_t recvmsg(int fd, struct msghdr *msg, int flags) { + if (!msg) return -EINVAL; + ssize_t r; socklen_t orig_controllen = msg->msg_controllen; #if LONG_MAX > INT_MAX -- 2.12.3
When msg is NULL, msg->msg_controllen exists to dereference a null pointer in recvmsg. The commit ae388becb529428ac926da102f1d025b3c3968da introduces this problem Signed-off-by: Qing Wu <wuqing30@huawei.com> Signed-off-by: Yan Zhu <zhuyan34@huawei.com> --- src/network/recvmsg.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/network/recvmsg.c b/src/network/recvmsg.c index 03641625..c36ffb8d 100644 --- a/src/network/recvmsg.c +++ b/src/network/recvmsg.c @@ -4,6 +4,7 @@ #include <sys/time.h> #include <string.h> #include "syscall.h" +#include <errno.h> hidden void __convert_scm_timestamps(struct msghdr *, socklen_t); @@ -49,6 +50,8 @@ void __convert_scm_timestamps(struct msghdr *msg, socklen_t csize) ssize_t recvmsg(int fd, struct msghdr *msg, int flags) { + if (!msg) return -EINVAL; + ssize_t r; socklen_t orig_controllen = msg->msg_controllen; #if LONG_MAX > INT_MAX -- 2.12.3
On Tue, Jan 12, 2021 at 07:58:26AM +0000, zhuyan (M) wrote:
>
> When msg is NULL, msg->msg_controllen exists to dereference a null pointer in recvmsg.
"The recvmsg() function takes the following arguments:
...
message
Points to a msghdr structure, ..."
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
On Mon, Jan 25, 2021 at 09:44:25PM -0500, Rich Felker wrote:
> On Tue, Jan 12, 2021 at 07:58:26AM +0000, zhuyan (M) wrote:
> >
> > When msg is NULL, msg->msg_controllen exists to dereference a null pointer in recvmsg.
>
> "The recvmsg() function takes the following arguments:
> ...
> message
> Points to a msghdr structure, ..."
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
It was pointed out to me on IRC that there is an "if (msg) condition
later (only on 64-bit archs), which makes this at least inconsistent.
So some cleanup is probably called for.
Also, the patch was incorrect even if you want to avoid crashing. It
returns a negated error code rather than setting errno and returning
-1.
Rich