Use SHA-2 instead of SHA-1

The use of SHA-1 in RHEL9 is deprecated

Author: bachradsusi

libselinux/include/selinux/label.h

@@ -120,13 +120,13 @@ extern int selabel_lookup_best_match_raw(struct selabel_handle *rec, char **con,
 					 const char *key, const char **aliases, int type);
 
 /**
- * selabel_digest - Retrieve the SHA1 digest and the list of specfiles used to
+ * selabel_digest - Retrieve the SHA256 digest and the list of specfiles used to
  *		    generate the digest. The SELABEL_OPT_DIGEST option must
  *		    be set in selabel_open() to initiate the digest generation.
  * @handle: specifies backend instance to query
- * @digest: returns a pointer to the SHA1 digest.
+ * @digest: returns a pointer to the SHA256 digest.
  * @digest_len: returns length of digest in bytes.
- * @specfiles: a list of specfiles used in the SHA1 digest generation.
+ * @specfiles: a list of specfiles used in the SHA256 digest generation.
  *	       The list is NULL terminated and will hold @num_specfiles entries.
  * @num_specfiles: number of specfiles in the list.
  *

libselinux/include/selinux/restorecon.h

@@ -41,8 +41,8 @@ extern int selinux_restorecon_parallel(const char *pathname,
  * restorecon_flags options
  */
 /*
- * Force the checking of labels even if the stored SHA1 digest
- * matches the specfiles SHA1 digest (requires CAP_SYS_ADMIN).
+ * Force the checking of labels even if the stored SHA256 digest
+ * matches the specfiles SHA256 digest (requires CAP_SYS_ADMIN).
  */
 #define SELINUX_RESTORECON_IGNORE_DIGEST		0x00001
 /*

libselinux/man/man3/selabel_digest.3

@@ -20,11 +20,11 @@ selabel_digest \- Return digest of specfiles and list of files used
 .BR selabel_digest ()
 performs an operation on the handle
 .IR hnd ,
-returning the results of the SHA1 digest pointed to by
+returning the results of the SHA256 digest pointed to by
 .IR digest ,
 whose length will be
 .IR digest_len .
-The list of specfiles used in the SHA1 digest calculation is returned in
+The list of specfiles used in the SHA256 digest calculation is returned in
 .I specfiles
 with the number of entries in
 .IR num_specfiles .

libselinux/man/man3/selabel_open.3

@@ -69,7 +69,7 @@ is used; a custom validation function can be provided via
 Note that an invalid context may not be treated as an error unless it is actually encountered during a lookup operation.
 .TP
 .B SELABEL_OPT_DIGEST
-A non-null value for this option enables the generation of an SHA1 digest of
+A non-null value for this option enables the generation of an SHA256 digest of
 the spec files loaded as described in
 .BR selabel_digest (3)
 .

libselinux/man/man3/selinux_restorecon.3

@@ -36,7 +36,7 @@ If this is a directory and the
 .B SELINUX_RESTORECON_RECURSE
 has been set (for descending through directories), then
 .BR selinux_restorecon ()
-will write an SHA1 digest of specfile entries calculated by
+will write an SHA256 digest of specfile entries calculated by
 .BR selabel_get_digests_all_partial_matches (3)
 to an extended attribute of
 .IR security.sehash
@@ -55,7 +55,7 @@ will take place.
 .br
 The
 .IR restorecon_flags
-that can be used to manage the usage of the SHA1 digest are:
+that can be used to manage the usage of the SHA256 digest are:
 .RS
 .B SELINUX_RESTORECON_SKIP_DIGEST
 .br
@@ -73,8 +73,8 @@ Do not check or update any extended attribute
 entries.
 .sp
 .B SELINUX_RESTORECON_IGNORE_DIGEST
-force the checking of labels even if the stored SHA1 digest matches the
-specfile entries SHA1 digest. The specfile entries digest will be written to the
+force the checking of labels even if the stored SHA256 digest matches the
+specfile entries SHA256 digest. The specfile entries digest will be written to the
 .IR security.sehash
 extended attribute once relabeling has been completed successfully provided the
 .B SELINUX_RESTORECON_NOCHANGE
@@ -95,7 +95,7 @@ default specfile context.
 .sp
 .B SELINUX_RESTORECON_RECURSE
 change file and directory labels recursively (descend directories)
-and if successful write an SHA1 digest of the specfile entries to an
+and if successful write an SHA256 digest of the specfile entries to an
 extended attribute as described in the
 .B NOTES
 section.
@@ -179,12 +179,12 @@ for fetching the ignored (skipped) error count after
 or
 .BR selinux_restorecon_parallel (3)
 completes with success. In case any errors were skipped during the file tree
-walk, the specfile entries SHA1 digest will not have been written to the
+walk, the specfile entries SHA256 digest will not have been written to the
 .IR security.sehash
 extended attribute.
 .RE
 .sp
-The behavior regarding the checking and updating of the SHA1 digest described
+The behavior regarding the checking and updating of the SHA256 digest described
 above is the default behavior. It is possible to change this by first calling
 .BR selabel_open (3)
 and not enabling the
@@ -247,7 +247,7 @@ To improve performance when relabeling file systems recursively (e.g. the
 .B SELINUX_RESTORECON_RECURSE
 flag is set)
 .BR selinux_restorecon ()
-will write a calculated SHA1 digest of the specfile entries returned by
+will write a calculated SHA256 digest of the specfile entries returned by
 .BR selabel_get_digests_all_partial_matches (3)
 to an extended attribute named
 .IR security.sehash
@@ -269,7 +269,7 @@ Should any of the specfile entries have changed, then when
 .BR selinux_restorecon ()
 is run again with the
 .B SELINUX_RESTORECON_RECURSE
-flag set, new SHA1 digests will be calculated and all files automatically
+flag set, new SHA256 digests will be calculated and all files automatically
 relabeled depending on the settings of the
 .B SELINUX_RESTORECON_SET_SPECFILE_CTX
 flag (provided

libselinux/man/man3/selinux_restorecon_xattr.3

@@ -119,7 +119,7 @@ By default
 .BR selinux_restorecon_xattr (3)
 will use the default set of specfiles described in
 .BR files_contexts (5)
-to calculate the SHA1 digests to be used for comparison.
+to calculate the SHA256 digests to be used for comparison.
 To change this default behavior
 .BR selabel_open (3)
 must be called specifying the required

libselinux/src/Makefile

@@ -130,7 +130,7 @@ DISABLE_FLAGS+= -DNO_MEDIA_BACKEND -DNO_DB_BACKEND -DNO_X_BACKEND \
 	-DBUILD_HOST
 SRCS= callbacks.c freecon.c label.c label_file.c \
 	label_backends_android.c regex.c label_support.c \
-	matchpathcon.c setrans_client.c sha1.c booleans.c
+	matchpathcon.c setrans_client.c sha256.c booleans.c
 LABEL_BACKEND_ANDROID=y
 endif
 

libselinux/src/label_file.c

@@ -1093,7 +1093,7 @@ static struct spec *lookup_common(struct selabel_handle *rec,
 
 /*
  * Returns true if the digest of all partial matched contexts is the same as
- * the one saved by setxattr, otherwise returns false. The length of the SHA1
+ * the one saved by setxattr, otherwise returns false. The length of the SHA256
  * digest will always be returned. The caller must free any returned digests.
  */
 static bool get_digests_all_partial_matches(struct selabel_handle *rec,
@@ -1102,39 +1102,39 @@ static bool get_digests_all_partial_matches(struct selabel_handle *rec,
 					    uint8_t **xattr_digest,
 					    size_t *digest_len)
 {
-	uint8_t read_digest[SHA1_HASH_SIZE];
+	uint8_t read_digest[SHA256_HASH_SIZE];
 	ssize_t read_size = getxattr(pathname, RESTORECON_PARTIAL_MATCH_DIGEST,
-				     read_digest, SHA1_HASH_SIZE
+				     read_digest, SHA256_HASH_SIZE
 #ifdef __APPLE__
 				     , 0, 0
 #endif /* __APPLE __ */
 				    );
-	uint8_t hash_digest[SHA1_HASH_SIZE];
+	uint8_t hash_digest[SHA256_HASH_SIZE];
 	bool status = selabel_hash_all_partial_matches(rec, pathname,
 						       hash_digest);
 
 	*xattr_digest = NULL;
 	*calculated_digest = NULL;
-	*digest_len = SHA1_HASH_SIZE;
+	*digest_len = SHA256_HASH_SIZE;
 
-	if (read_size == SHA1_HASH_SIZE) {
-		*xattr_digest = calloc(1, SHA1_HASH_SIZE + 1);
+	if (read_size == SHA256_HASH_SIZE) {
+		*xattr_digest = calloc(1, SHA256_HASH_SIZE + 1);
 		if (!*xattr_digest)
 			goto oom;
 
-		memcpy(*xattr_digest, read_digest, SHA1_HASH_SIZE);
+		memcpy(*xattr_digest, read_digest, SHA256_HASH_SIZE);
 	}
 
 	if (status) {
-		*calculated_digest = calloc(1, SHA1_HASH_SIZE + 1);
+		*calculated_digest = calloc(1, SHA256_HASH_SIZE + 1);
 		if (!*calculated_digest)
 			goto oom;
 
-		memcpy(*calculated_digest, hash_digest, SHA1_HASH_SIZE);
+		memcpy(*calculated_digest, hash_digest, SHA256_HASH_SIZE);
 	}
 
-	if (status && read_size == SHA1_HASH_SIZE &&
-	    memcmp(read_digest, hash_digest, SHA1_HASH_SIZE) == 0)
+	if (status && read_size == SHA256_HASH_SIZE &&
+	    memcmp(read_digest, hash_digest, SHA256_HASH_SIZE) == 0)
 		return true;
 
 	return false;
@@ -1154,22 +1154,22 @@ static bool hash_all_partial_matches(struct selabel_handle *rec, const char *key
 		return false;
 	}
 
-	Sha1Context context;
-	Sha1Initialise(&context);
+	Sha256Context context;
+	Sha256Initialise(&context);
 	size_t i;
 	for (i = 0; i < total_matches; i++) {
 		char* regex_str = matches[i]->regex_str;
 		mode_t mode = matches[i]->mode;
 		char* ctx_raw = matches[i]->lr.ctx_raw;
 
-		Sha1Update(&context, regex_str, strlen(regex_str) + 1);
-		Sha1Update(&context, &mode, sizeof(mode_t));
-		Sha1Update(&context, ctx_raw, strlen(ctx_raw) + 1);
+		Sha256Update(&context, regex_str, strlen(regex_str) + 1);
+		Sha256Update(&context, &mode, sizeof(mode_t));
+		Sha256Update(&context, ctx_raw, strlen(ctx_raw) + 1);
 	}
 
-	SHA1_HASH sha1_hash;
-	Sha1Finalise(&context, &sha1_hash);
-	memcpy(digest, sha1_hash.bytes, SHA1_HASH_SIZE);
+	SHA256_HASH sha256_hash;
+	Sha256Finalise(&context, &sha256_hash);
+	memcpy(digest, sha256_hash.bytes, SHA256_HASH_SIZE);
 
 	free(matches);
 	return true;

libselinux/src/label_internal.h

@@ -13,7 +13,7 @@
 #include <stdio.h>
 #include <selinux/selinux.h>
 #include <selinux/label.h>
-#include "sha1.h"
+#include "sha256.h"
 
 #if defined(ANDROID) || defined(__APPLE__)
 // Android and Mac do not have fgets_unlocked()
@@ -47,15 +47,15 @@ int selabel_service_init(struct selabel_handle *rec,
  */
 
 /*
- * Calculate an SHA1 hash of all the files used to build the specs.
+ * Calculate an SHA256 hash of all the files used to build the specs.
  * The hash value is held in rec->digest if SELABEL_OPT_DIGEST set. To
  * calculate the hash the hashbuf will hold a concatenation of all the files
  * used. This is released once the value has been calculated.
  */
-#define DIGEST_SPECFILE_SIZE SHA1_HASH_SIZE
+#define DIGEST_SPECFILE_SIZE SHA256_HASH_SIZE
 #define DIGEST_FILES_MAX 8
 struct selabel_digest {
-	unsigned char *digest;	/* SHA1 digest of specfiles */
+	unsigned char *digest;	/* SHA256 digest of specfiles */
 	unsigned char *hashbuf;	/* buffer to hold specfiles */
 	size_t hashbuf_size;	/* buffer size */
 	size_t specfile_cnt;	/* how many specfiles processed */
@@ -110,7 +110,7 @@ struct selabel_handle {
 	 */
 	char *spec_file;
 
-	/* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set */
+	/* ptr to SHA256 hash information if SELABEL_OPT_DIGEST set */
 	struct selabel_digest *digest;
 };
 

libselinux/src/label_support.c

@@ -114,27 +114,27 @@ int  read_spec_entries(char *line_buf, const char **errbuf, int num_args, ...)
 /* Once all the specfiles are in the hash_buf, generate the hash. */
 void  digest_gen_hash(struct selabel_digest *digest)
 {
-	Sha1Context context;
+	Sha256Context context;
 	size_t remaining_size;
 	const unsigned char *ptr;
 
 	/* If SELABEL_OPT_DIGEST not set then just return */
 	if (!digest)
 		return;
 
-	Sha1Initialise(&context);
+	Sha256Initialise(&context);
 
 	/* Process in blocks of UINT32_MAX bytes */
 	remaining_size = digest->hashbuf_size;
 	ptr = digest->hashbuf;
 	while (remaining_size > UINT32_MAX) {
-		Sha1Update(&context, ptr, UINT32_MAX);
+		Sha256Update(&context, ptr, UINT32_MAX);
 		remaining_size -= UINT32_MAX;
 		ptr += UINT32_MAX;
 	}
-	Sha1Update(&context, ptr, remaining_size);
+	Sha256Update(&context, ptr, remaining_size);
 
-	Sha1Finalise(&context, (SHA1_HASH *)digest->digest);
+	Sha256Finalise(&context, (SHA256_HASH *)digest->digest);
 	free(digest->hashbuf);
 	digest->hashbuf = NULL;
 }

libselinux/src/selinux_restorecon.c

@@ -37,7 +37,7 @@
 #include "callbacks.h"
 #include "selinux_internal.h"
 #include "label_file.h"
-#include "sha1.h"
+#include "sha256.h"
 
 #define STAR_COUNT 1024
 
@@ -304,7 +304,7 @@ static uint64_t exclude_non_seclabel_mounts(void)
 static int add_xattr_entry(const char *directory, bool delete_nonmatch,
 			   bool delete_all)
 {
-	char *sha1_buf = NULL;
+	char *sha256_buf = NULL;
 	size_t i, digest_len = 0;
 	int rc;
 	enum digest_result digest_result;
@@ -328,15 +328,15 @@ static int add_xattr_entry(const char *directory, bool delete_nonmatch,
 	}
 
 	/* Convert entry to a hex encoded string. */
-	sha1_buf = malloc(digest_len * 2 + 1);
-	if (!sha1_buf) {
+	sha256_buf = malloc(digest_len * 2 + 1);
+	if (!sha256_buf) {
 		free(xattr_digest);
 		free(calculated_digest);
 		goto oom;
 	}
 
 	for (i = 0; i < digest_len; i++)
-		sprintf((&sha1_buf[i * 2]), "%02x", xattr_digest[i]);
+		sprintf((&sha256_buf[i * 2]), "%02x", xattr_digest[i]);
 
 	digest_result = match ? MATCH : NOMATCH;
 
@@ -356,23 +356,23 @@ static int add_xattr_entry(const char *directory, bool delete_nonmatch,
 	/* Now add entries to link list. */
 	new_entry = malloc(sizeof(struct dir_xattr));
 	if (!new_entry) {
-		free(sha1_buf);
+		free(sha256_buf);
 		goto oom;
 	}
 	new_entry->next = NULL;
 
 	new_entry->directory = strdup(directory);
 	if (!new_entry->directory) {
 		free(new_entry);
-		free(sha1_buf);
+		free(sha256_buf);
 		goto oom;
 	}
 
-	new_entry->digest = strdup(sha1_buf);
+	new_entry->digest = strdup(sha256_buf);
 	if (!new_entry->digest) {
 		free(new_entry->directory);
 		free(new_entry);
-		free(sha1_buf);
+		free(sha256_buf);
 		goto oom;
 	}
 
@@ -386,7 +386,7 @@ static int add_xattr_entry(const char *directory, bool delete_nonmatch,
 		dir_xattr_last = new_entry;
 	}
 
-	free(sha1_buf);
+	free(sha256_buf);
 	return 0;
 
 oom:
@@ -776,7 +776,7 @@ static int restorecon_sb(const char *pathname, const struct stat *sb,
 
 struct dir_hash_node {
 	char *path;
-	uint8_t digest[SHA1_HASH_SIZE];
+	uint8_t digest[SHA256_HASH_SIZE];
 	struct dir_hash_node *next;
 };
 /*
@@ -1282,7 +1282,7 @@ static int selinux_restorecon_common(const char *pathname_orig,
 			if (setxattr(current->path,
 			    RESTORECON_PARTIAL_MATCH_DIGEST,
 			    current->digest,
-			    SHA1_HASH_SIZE, 0) < 0) {
+			    SHA256_HASH_SIZE, 0) < 0) {
 				selinux_log(SELINUX_ERROR,
 					    "setxattr failed: %s: %m\n",
 					    current->path);