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While working on some other SCTP code, I noticed that some structures shared with user space are leaking uninitialized stack or heap buffer. In particular, struct sctp_sndrcvinfo has a 2 bytes hole between .sinfo_flags and .sinfo_ppid that remains unfilled by us in sctp_ulpevent_read_sndrcvinfo() when putting this into cmsg. But also struct sctp_remote_error contains a 2 bytes hole that we don't fill but place into a skb through skb_copy_expand() via sctp_ulpevent_make_remote_error(). Both structures are defined by the IETF in RFC6458: * Section 5.3.2. SCTP Header Information Structure: The sctp_sndrcvinfo structure is defined below: struct sctp_sndrcvinfo { uint16_t sinfo_stream; uint16_t sinfo_ssn; uint16_t sinfo_flags; <-- 2 bytes hole --> uint32_t sinfo_ppid; uint32_t sinfo_context; uint32_t sinfo_timetolive; uint32_t sinfo_tsn; uint32_t sinfo_cumtsn; sctp_assoc_t sinfo_assoc_id; }; * 6.1.3. SCTP_REMOTE_ERROR: A remote peer may send an Operation Error message to its peer. This message indicates a variety of error conditions on an association. The entire ERROR chunk as it appears on the wire is included in an SCTP_REMOTE_ERROR event. Please refer to the SCTP specification [RFC4960] and any extensions for a list of possible error formats. An SCTP error notification has the following format: struct sctp_remote_error { uint16_t sre_type; uint16_t sre_flags; uint32_t sre_length; uint16_t sre_error; <-- 2 bytes hole --> sctp_assoc_t sre_assoc_id; uint8_t sre_data[]; }; Fix this by setting both to 0 before filling them out. We also have other structures shared between user and kernel space in SCTP that contains holes (e.g. struct sctp_paddrthlds), but we copy that buffer over from user space first and thus don't need to care about it in that cases. While at it, we can also remove lengthy comments copied from the draft, instead, we update the comment with the correct RFC number where one can look it up. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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.. | ||
associola.c | ||
auth.c | ||
bind_addr.c | ||
chunk.c | ||
command.c | ||
debug.c | ||
endpointola.c | ||
input.c | ||
inqueue.c | ||
ipv6.c | ||
Kconfig | ||
Makefile | ||
objcnt.c | ||
output.c | ||
outqueue.c | ||
primitive.c | ||
probe.c | ||
proc.c | ||
protocol.c | ||
sm_make_chunk.c | ||
sm_sideeffect.c | ||
sm_statefuns.c | ||
sm_statetable.c | ||
socket.c | ||
ssnmap.c | ||
sysctl.c | ||
transport.c | ||
tsnmap.c | ||
ulpevent.c | ||
ulpqueue.c |