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Merge pull request #23226 from keszybz/libsystemd-length-assert

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Add assert about DHCP packet length in libsystemd-network
This commit is contained in:
Yu Watanabe 2022-04-30 03:03:18 +09:00 committed by GitHub
commit df8774263c
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1 changed files with 5 additions and 8 deletions
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13
src/libsystemd-network/dhcp-packet.c
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@ -129,6 +129,7 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum, ui
size_t hdrlen;
assert(packet);
assert(len >= sizeof(DHCPPacket));
/* IP */
@ -144,14 +145,12 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum, ui
hdrlen = packet->ip.ihl * 4;
if (hdrlen < 20)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"ignoring packet: IPv4 IHL (%zu bytes) "
"smaller than minimum (20 bytes)",
"ignoring packet: IPv4 IHL (%zu bytes) smaller than minimum (20 bytes)",
hdrlen);
if (len < hdrlen)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"ignoring packet: packet (%zu bytes) "
"smaller than expected (%zu) by IP header",
"ignoring packet: packet (%zu bytes) smaller than expected (%zu) by IP header",
len, hdrlen);
/* UDP */
@ -162,14 +161,12 @@ int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum, ui
if (len < hdrlen + be16toh(packet->udp.len))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"ignoring packet: packet (%zu bytes) "
"smaller than expected (%zu) by UDP header",
"ignoring packet: packet (%zu bytes) smaller than expected (%zu) by UDP header",
len, hdrlen + be16toh(packet->udp.len));
if (be16toh(packet->udp.dest) != port)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"ignoring packet: to port %u, which "
"is not the DHCP client port (%u)",
"ignoring packet: to port %u, which is not the DHCP client port (%u)",
be16toh(packet->udp.dest), port);
/* checksums - computing these is relatively expensive, so only do it