Re: [PATCH bpf-next v3 2/2] bpf: Check return from set_memory_rox()
From: Martin KaFai Lau <martin.lau@linux.dev>
Date: 2024-03-16 00:56:37
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bpf, lkml, netdev
On 3/15/24 2:11 PM, Martin KaFai Lau wrote:
On 3/15/24 1:55 PM, Martin KaFai Lau wrote:quoted
On 3/15/24 10:06 AM, Christophe Leroy wrote:quoted
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index 43356faaa057..ca1d9b87c475 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c@@ -742,8 +742,11 @@ static long bpf_struct_ops_map_update_elem(structbpf_map *map, void *key, if (err) goto reset_unlock; } - for (i = 0; i < st_map->image_pages_cnt; i++) - arch_protect_bpf_trampoline(st_map->image_pages[i], PAGE_SIZE); + for (i = 0; i < st_map->image_pages_cnt && !err; i++)
I was about to apply but I still think checking "&& !err" is not right given how "err" is used in the earlier code of this function. The err may not be 0 in the first iteration of this for loop. Take a look at the "if (err > 0)" check in the "for_each_member(i, t, member)" loop above.
quoted
quoted
+ err = arch_protect_bpf_trampoline(st_map->image_pages[i], PAGE_SIZE); + + if (err) + goto reset_unlock;This part does not look right. The "if (err)" check should be inside the for loop.
Instead of adding an extra "err = 0;" before the for loop. It is better to move this "if (err) goto reset_unlock;" into the for loop and remove the "&& !err" test above.
ah. Please ignore. missed the "!err" in the for loop.
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