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| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2024-03-16 08:35:41 +0100 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2024-03-18 14:18:47 -0700 |
| commit | c733239f8f530872a1f80d8c45dcafbaff368737 (patch) | |
| tree | bd2fb53ca8a95c663a415f5b8a5479b338cfa7fd /kernel/bpf/core.c | |
| parent | e3362acd796789dc0562eb1a3937007b0beb0c5b (diff) | |
| download | lwn-c733239f8f530872a1f80d8c45dcafbaff368737.tar.gz lwn-c733239f8f530872a1f80d8c45dcafbaff368737.zip | |
bpf: Check return from set_memory_rox()
arch_protect_bpf_trampoline() and alloc_new_pack() call
set_memory_rox() which can fail, leading to unprotected memory.
Take into account return from set_memory_rox() function and add
__must_check flag to arch_protect_bpf_trampoline().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/fe1c163c83767fde5cab31d209a4a6be3ddb3a73.1710574353.git.christophe.leroy@csgroup.eu
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Diffstat (limited to 'kernel/bpf/core.c')
| -rw-r--r-- | kernel/bpf/core.c | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 63f100def31b..5aacb1d3c4cc 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -908,23 +908,30 @@ static LIST_HEAD(pack_list); static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) { struct bpf_prog_pack *pack; + int err; pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)), GFP_KERNEL); if (!pack) return NULL; pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE); - if (!pack->ptr) { - kfree(pack); - return NULL; - } + if (!pack->ptr) + goto out; bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); - list_add_tail(&pack->list, &pack_list); set_vm_flush_reset_perms(pack->ptr); - set_memory_rox((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE); + err = set_memory_rox((unsigned long)pack->ptr, + BPF_PROG_PACK_SIZE / PAGE_SIZE); + if (err) + goto out; + list_add_tail(&pack->list, &pack_list); return pack; + +out: + bpf_jit_free_exec(pack->ptr); + kfree(pack); + return NULL; } void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) @@ -939,9 +946,16 @@ void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) size = round_up(size, PAGE_SIZE); ptr = bpf_jit_alloc_exec(size); if (ptr) { + int err; + bpf_fill_ill_insns(ptr, size); set_vm_flush_reset_perms(ptr); - set_memory_rox((unsigned long)ptr, size / PAGE_SIZE); + err = set_memory_rox((unsigned long)ptr, + size / PAGE_SIZE); + if (err) { + bpf_jit_free_exec(ptr); + ptr = NULL; + } } goto out; } |