diff mbox series

[net-next,v2,1/3] ipv4: Mask upper DSCP bits and ECN bits in NETLINK_FIB_LOOKUP family

Message ID 20240814125224.972815-2-idosch@nvidia.com (mailing list archive)
State Accepted
Commit 8fed54758cd248cd311a2b5c1e180abef1866237
Delegated to: Netdev Maintainers
Headers show
Series Preparations for FIB rule DSCP selector | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 29 this patch: 29
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 29 this patch: 29
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 29 this patch: 29
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-08-20--09-00 (tests: 712)

Commit Message

Ido Schimmel Aug. 14, 2024, 12:52 p.m. UTC 
The NETLINK_FIB_LOOKUP netlink family can be used to perform a FIB
lookup according to user provided parameters and communicate the result
back to user space.

However, unlike other users of the FIB lookup API, the upper DSCP bits
and the ECN bits of the DS field are not masked, which can result in the
wrong result being returned.

Solve this by masking the upper DSCP bits and the ECN bits using
IPTOS_RT_MASK.

The structure that communicates the request and the response is not
exported to user space, so it is unlikely that this netlink family is
actually in use [1].

[1] https://lore.kernel.org/netdev/ZpqpB8vJU%2FQ6LSqa@debian/

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
---
 net/ipv4/fib_frontend.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 7ad2cafb9276..da540ddb7af6 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1343,7 +1343,7 @@  static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
 	struct flowi4           fl4 = {
 		.flowi4_mark = frn->fl_mark,
 		.daddr = frn->fl_addr,
-		.flowi4_tos = frn->fl_tos,
+		.flowi4_tos = frn->fl_tos & IPTOS_RT_MASK,
 		.flowi4_scope = frn->fl_scope,
 	};
 	struct fib_table *tb;