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ima: fix blocking of security.ima xattrs of unsupported algorithms

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Limit validating the hash algorithm to just security.ima xattr, not
the security.evm xattr or any of the protected EVM security xattrs,
nor posix acls.

Fixes: 50f742dd91 ("IMA: block writes of the security.ima xattr with unsupported algorithms")
Reported-by: Christian Brauner <brauner@kernel.org>
Acked-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
This commit is contained in:
Mimi Zohar 2022-08-17 17:18:42 -04:00
parent 1c23f9e627
commit 5926586f29
1 changed files with 8 additions and 4 deletions
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12
security/integrity/ima/ima_appraise.c
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@ -750,22 +750,26 @@ int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
const struct evm_ima_xattr_data *xvalue = xattr_value;
int digsig = 0;
int result;
int err;
result = ima_protect_xattr(dentry, xattr_name, xattr_value,
xattr_value_len);
if (result == 1) {
if (!xattr_value_len || (xvalue->type >= IMA_XATTR_LAST))
return -EINVAL;
err = validate_hash_algo(dentry, xvalue, xattr_value_len);
if (err)
return err;
digsig = (xvalue->type == EVM_IMA_XATTR_DIGSIG);
} else if (!strcmp(xattr_name, XATTR_NAME_EVM) && xattr_value_len > 0) {
digsig = (xvalue->type == EVM_XATTR_PORTABLE_DIGSIG);
}
if (result == 1 || evm_revalidate_status(xattr_name)) {
result = validate_hash_algo(dentry, xvalue, xattr_value_len);
if (result)
return result;
ima_reset_appraise_flags(d_backing_inode(dentry), digsig);
if (result == 1)
result = 0;
}
return result;
}