From: Qihang Date: Wed, 1 Jul 2026 02:26:17 +0000 (+0800) Subject: gue: validate REMCSUM private option length X-Git-Tag: v7.2-rc3~29^2~33 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d335dcc6f521571d57117b8deeebc940836e5450;p=thirdparty%2Fkernel%2Fstable.git gue: validate REMCSUM private option length GUE private flags can indicate that remote checksum offload metadata is present. The private flags field itself is accounted for by guehdr_flags_len(), but guehdr_priv_flags_len() currently returns 0 even when GUE_PFLAG_REMCSUM is set. This lets a packet with only the private flags field pass validate_gue_flags(), after which gue_remcsum() and gue_gro_remcsum() read the missing REMCSUM start/offset fields from the following bytes. Account for GUE_PLEN_REMCSUM when GUE_PFLAG_REMCSUM is present so that malformed packets are rejected during option validation. Fixes: c1aa8347e73e ("gue: Protocol constants for remote checksum offload") Signed-off-by: Qihang Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- diff --git a/include/net/gue.h b/include/net/gue.h index dfca298bec9c..caefd6da8693 100644 --- a/include/net/gue.h +++ b/include/net/gue.h @@ -80,7 +80,7 @@ static inline size_t guehdr_flags_len(__be16 flags) static inline size_t guehdr_priv_flags_len(__be32 flags) { - return 0; + return (flags & GUE_PFLAG_REMCSUM) ? GUE_PLEN_REMCSUM : 0; } /* Validate standard and private flags. Returns non-zero (meaning invalid)