| Message ID | 20250306112520.188728-1-torben.nielsen@prevas.dk (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | David Ahern |
| Headers | show |
| Series | [iproute2-next] tc: nat: Fix mask calculation | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
diff --git a/tc/m_nat.c b/tc/m_nat.c index 69d54c6f..da947aea 100644 --- a/tc/m_nat.c +++ b/tc/m_nat.c @@ -55,7 +55,7 @@ parse_nat_args(int *argc_p, char ***argv_p, struct tc_nat *sel) goto bad_val; sel->old_addr = addr.data[0]; - sel->mask = htonl(~0u << (32 - addr.bitlen)); + sel->mask = htonl(~(uint64_t)0 << (32 - addr.bitlen)); NEXT_ARG();
In parse_nat_args the network mask is calculated as sel->mask = htonl(~0u << (32 - addr.bitlen)); According to ISO/IEC 9899:TC3 6.5.7 Bitwise shift operators: The integer promotions are performed on each of the operands. The type of the result is that of the promoted left operand. If the value of the right operand is negative or is greater than or equal to the width of the promoted left operand, the behavior is undefined Specifically this means that the mask is undefined for addr.bitlen = 0 On x86_64 the result is 0xffffffff, on armv7l it is 0. Promoting the left operand of the shift operator solves this issue. Signed-off-by: Torben Nielsen <torben.nielsen@prevas.dk> --- tc/m_nat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)