Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.9 60/74] evm: Check size of security.evm before using it | Date | Sat, 31 Oct 2020 12:36:42 +0100 |
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From: Roberto Sassu <roberto.sassu@huawei.com>
commit 455b6c9112eff8d249e32ba165742085678a80a4 upstream.
This patch checks the size for the EVM_IMA_XATTR_DIGSIG and EVM_XATTR_PORTABLE_DIGSIG types to ensure that the algorithm is read from the buffer returned by vfs_getxattr_alloc().
Cc: stable@vger.kernel.org # 4.19.x Fixes: 5feeb61183dde ("evm: Allow non-SHA1 digital signatures") Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- security/integrity/evm/evm_main.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -181,6 +181,12 @@ static enum integrity_status evm_verify_ break; case EVM_IMA_XATTR_DIGSIG: case EVM_XATTR_PORTABLE_DIGSIG: + /* accept xattr with non-empty signature field */ + if (xattr_len <= sizeof(struct signature_v2_hdr)) { + evm_status = INTEGRITY_FAIL; + goto out; + } + hdr = (struct signature_v2_hdr *)xattr_data; digest.hdr.algo = hdr->hash_algo; rc = evm_calc_hash(dentry, xattr_name, xattr_value,
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