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bpf: Use sha1() instead of sha1_transform() in bpf_prog_calc_tag()

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Now that there's a proper SHA-1 library API, just use that instead of
the low-level SHA-1 compression function.  This eliminates the need for
bpf_prog_calc_tag() to implement the SHA-1 padding itself.  No
functional change; the computed tags remain the same.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20250811201615.564461-1-ebiggers@kernel.org
This commit is contained in:
Eric Biggers
2025-08-11 13:16:15 -07:00
committed by Andrii Nakryiko
parent 0780f54ab1
commit d47cc4dea1
2 changed files with 9 additions and 47 deletions
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50
kernel/bpf/core.c
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@@ -18,6 +18,7 @@
*/
#include <uapi/linux/btf.h>
#include <crypto/sha1.h>
#include <linux/filter.h>
#include <linux/skbuff.h>
#include <linux/vmalloc.h>
@@ -293,28 +294,19 @@ void __bpf_prog_free(struct bpf_prog *fp)
int bpf_prog_calc_tag(struct bpf_prog *fp)
{
const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
u32 raw_size = bpf_prog_tag_scratch_size(fp);
u32 digest[SHA1_DIGEST_WORDS];
u32 ws[SHA1_WORKSPACE_WORDS];
u32 i, bsize, psize, blocks;
size_t size = bpf_prog_insn_size(fp);
u8 digest[SHA1_DIGEST_SIZE];
struct bpf_insn *dst;
bool was_ld_map;
u8 *raw, *todo;
__be32 *result;
__be64 *bits;
u32 i;
raw = vmalloc(raw_size);
if (!raw)
dst = vmalloc(size);
if (!dst)
return -ENOMEM;
sha1_init_raw(digest);
memset(ws, 0, sizeof(ws));
/* We need to take out the map fd for the digest calculation
* since they are unstable from user space side.
*/
dst = (void *)raw;
for (i = 0, was_ld_map = false; i < fp->len; i++) {
dst[i] = fp->insnsi[i];
if (!was_ld_map &&
@@ -334,33 +326,9 @@ int bpf_prog_calc_tag(struct bpf_prog *fp)
was_ld_map = false;
}
}
psize = bpf_prog_insn_size(fp);
memset(&raw[psize], 0, raw_size - psize);
raw[psize++] = 0x80;
bsize = round_up(psize, SHA1_BLOCK_SIZE);
blocks = bsize / SHA1_BLOCK_SIZE;
todo = raw;
if (bsize - psize >= sizeof(__be64)) {
bits = (__be64 *)(todo + bsize - sizeof(__be64));
} else {
bits = (__be64 *)(todo + bsize + bits_offset);
blocks++;
}
*bits = cpu_to_be64((psize - 1) << 3);
while (blocks--) {
sha1_transform(digest, todo, ws);
todo += SHA1_BLOCK_SIZE;
}
result = (__force __be32 *)digest;
for (i = 0; i < SHA1_DIGEST_WORDS; i++)
result[i] = cpu_to_be32(digest[i]);
memcpy(fp->tag, result, sizeof(fp->tag));
vfree(raw);
sha1((const u8 *)dst, size, digest);
memcpy(fp->tag, digest, sizeof(fp->tag));
vfree(dst);
return 0;
}