From: Raphael Zimmer Date: Wed, 27 May 2026 14:06:17 +0000 (+0200) Subject: libceph: Fix multiplication overflow in decode_new_up_state_weight() X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=98917a499ec7064c14fc56d180a4fd636fc2784c;p=thirdparty%2Fkernel%2Flinux.git libceph: Fix multiplication overflow in decode_new_up_state_weight() If a message of type CEPH_MSG_OSD_MAP contains a (maliciously) corrupted osdmap, out-of-bounds memory accesses may occur in decode_new_up_state_weight(). This happens because the bounds check for the new_state part is based on calculating its length depending on a len value read from the incoming message. This calculation may overflow leading to an incorrect bounds check. Subsequently, out-of-bounds reads may occur when decoding this part. This patch switches the multiplication to use check_mul_overflow() to abort processing the osdmap if an overflow occurred. Therefore, osdmaps/messages containing large values for len that result in a multiplication overflow are treated as invalid. [ idryomov: rename new_state_len -> new_state_item_size, formatting ] Cc: stable@vger.kernel.org Fixes: 930c53286977 ("libceph: apply new_state before new_up_client on incrementals") Signed-off-by: Raphael Zimmer Reviewed-by: Viacheslav Dubeyko Signed-off-by: Ilya Dryomov --- diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c index 8b5b0587a0cf..8e77096718c4 100644 --- a/net/ceph/osdmap.c +++ b/net/ceph/osdmap.c @@ -1842,6 +1842,8 @@ static int decode_new_up_state_weight(void **p, void *end, u8 struct_v, void *new_up_client; void *new_state; void *new_weight_end; + const u32 new_state_item_size = + sizeof(u32) + (struct_v >= 5 ? sizeof(u32) : sizeof(u8)); u32 len; int ret; int i; @@ -1862,7 +1864,8 @@ static int decode_new_up_state_weight(void **p, void *end, u8 struct_v, new_state = *p; ceph_decode_32_safe(p, end, len, e_inval); - len *= sizeof(u32) + (struct_v >= 5 ? sizeof(u32) : sizeof(u8)); + if (check_mul_overflow(len, new_state_item_size, &len)) + goto e_inval; ceph_decode_need(p, end, len, e_inval); *p += len;