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read list of existing extended attributes

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getxattr() might return runtime value which does not really exist
on file system. It happens for SMACK LSM. Reading the list of existing
attributes allows to prevent such to happen.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
This commit is contained in:
Dmitry Kasatkin 2012-04-04 16:48:38 +03:00
parent d61b9c0be7
commit e576ac9771
1 changed files with 39 additions and 3 deletions
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42
src/evmctl.c
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@ -372,6 +372,18 @@ static int sign_hash(const unsigned char *hash, int size, const char *keyfile, u
return len;
}
static int find_xattr(const char *list, int list_size, const char *xattr)
{
int len;
for (; list_size > 0; len++, list_size -= len, list += len) {
len = strlen(list);
if (!strcmp(list, xattr))
return 1;
}
return 0;
}
static int calc_evm_hash(const char *file, unsigned char *hash)
{
struct stat st;
@ -382,6 +394,8 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
unsigned int mdlen;
char **xattrname;
char xattr_value[1024];
char list[1024];
ssize_t list_size;
fd = open(file, 0);
if (fd < 0) {
@ -403,6 +417,12 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
log_info("generation: %u\n", generation);
list_size = llistxattr(file, list, sizeof(list));
if (list_size <= 0) {
log_errno("llistxattr() failed");
return -1;
}
md = EVP_get_digestbyname("sha1");
if (!md) {
log_errno("EVP_get_digestbyname() failed");
@ -414,11 +434,15 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
log_errno("EVP_DigestInit() failed");
return -1;
}
for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) {
err = getxattr(file, *xattrname, xattr_value, sizeof(xattr_value));
if (err < 0) {
log_info("no attr: %s\n", *xattrname);
log_info("no xattr: %s\n", *xattrname);
continue;
}
if (!find_xattr(list, list_size, *xattrname)) {
log_info("skipping xattr: %s\n", *xattrname);
continue;
}
/*log_debug("name: %s, value: %s, size: %d\n", *xattrname, xattr_value, err);*/
@ -960,6 +984,8 @@ static int calc_evm_hmac(const char *file, const char *keyfile, unsigned char *h
char *key;
int keylen;
unsigned char evmkey[MAX_KEY_SIZE];
char list[1024];
ssize_t list_size;
key = file2bin(keyfile, &keylen);
if (!key) {
@ -996,6 +1022,12 @@ static int calc_evm_hmac(const char *file, const char *keyfile, unsigned char *h
log_info("generation: %u\n", generation);
list_size = llistxattr(file, list, sizeof(list));
if (list_size <= 0) {
log_errno("llistxattr() failed");
return -1;
}
err = HMAC_Init(&ctx, evmkey, sizeof(evmkey), EVP_sha1());
if (!err) {
log_errno("HMAC_Init() failed");
@ -1005,7 +1037,11 @@ static int calc_evm_hmac(const char *file, const char *keyfile, unsigned char *h
for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) {
err = getxattr(file, *xattrname, xattr_value, sizeof(xattr_value));
if (err < 0) {
log_info("no attr: %s\n", *xattrname);
log_info("no xattr: %s\n", *xattrname);
continue;
}
if (!find_xattr(list, list_size, *xattrname)) {
log_info("skipping xattr: %s\n", *xattrname);
continue;
}
/*log_debug("name: %s, value: %s, size: %d\n", *xattrname, xattr_value, err);*/