tpm2_identity_util!: add buffer size check in hmac_outer_integrity to prevent potential oob#3571
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JuergenReppSIT merged 1 commit intoMar 27, 2026
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hmac_outer_integrity() concatenates two caller-supplied buffers into a fixed-size stack buffer of TPM2_MAX_DIGEST_BUFFER (1024) bytes using memcpy without checking their combined size. This commit adds a buffer size check before memcpy to prevent potential oob. To propagate errors to the caller, the return type of hmac_outer_integrity() and tpm2_identity_util_calculate_outer_integrity() from void to bool. The latter change breaks compatibility with the public API. Signed-off-by: Takuma IMAMURA <209989118+hyperfinitism@users.noreply.github.com>
JuergenReppSIT
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Mar 27, 2026
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@hyperfinitism Thank you for the PR. |
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Summary
hmac_outer_integrity()concatenates two caller-supplied buffers into a fixed-size stack buffer ofTPM2_MAX_DIGEST_BUFFER(1024) bytes usingmemcpywithout checking their combined size.This PR adds a buffer size check before the
memcpycalls to prevent a potential oob. To propagate the error to callers, the return type ofhmac_outer_integrity()and its public wrappertpm2_identity_util_calculate_outer_integrity()is changed fromvoidtobool.Changes
hmac_outer_integrity(): emit an error log message and returnfalseifbuffer1_size + buffer2_size > TPM2_MAX_DIGEST_BUFFERhmac_outer_integrity()fromvoidtobooltpm2_identity_util_calculate_outer_integrity()fromvoidtobooland update the declaration intpm2_identity_util.h