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LoadPin: Annotate struct dm_verity_loadpin_trusted_root_digest with __counted_by
Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions). As found with Coccinelle[1], add __counted_by for struct dm_verity_loadpin_trusted_root_digest. Additionally, since the element count member must be set before accessing the annotated flexible array member, move its initialization earlier. [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@kernel.org> Cc: dm-devel@redhat.com Cc: Paul Moore <paul@paul-moore.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: linux-security-module@vger.kernel.org Link: https://lore.kernel.org/r/20230817235955.never.762-kees@kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
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-3
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include/linux/dm-verity-loadpin.h

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,7 @@ extern struct list_head dm_verity_loadpin_trusted_root_digests;
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struct dm_verity_loadpin_trusted_root_digest {
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struct list_head node;
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unsigned int len;
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u8 data[];
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u8 data[] __counted_by(len);
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};
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#if IS_ENABLED(CONFIG_SECURITY_LOADPIN_VERITY)

security/loadpin/loadpin.c

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -336,15 +336,14 @@ static int read_trusted_verity_root_digests(unsigned int fd)
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rc = -ENOMEM;
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goto err;
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}
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trd->len = len;
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if (hex2bin(trd->data, d, len)) {
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kfree(trd);
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rc = -EPROTO;
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goto err;
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}
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346-
trd->len = len;
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348347
list_add_tail(&trd->node, &dm_verity_loadpin_trusted_root_digests);
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}
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