Messages in this thread Patch in this message | | | From | Roberto Sassu <> | Subject | [PATCH 04/11] evm: Check size of security.evm before using it | Date | Thu, 18 Jun 2020 18:01:26 +0200 |
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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> --- security/integrity/evm/evm_main.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 744c105b48d1..4e9f5e8b21d5 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -181,6 +181,12 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, 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, -- 2.17.1
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