diff options
| author | Justin Stitt <justinstitt@google.com> | 2024-03-21 00:38:54 +0000 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2024-04-24 16:57:38 -0700 |
| commit | f700b71927017ca5697e8a24fd2ad5d3e06489d6 (patch) | |
| tree | 8cc4493a1072272ba229f3334dfbff50838c8297 /fs/ecryptfs | |
| parent | 7dcbf17e3f917f691d2ae9ed4a34283bd0e74a95 (diff) | |
fs: ecryptfs: replace deprecated strncpy with strscpy
strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces. A good alternative is strscpy() as it guarantees
NUL-termination on the destination buffer.
In crypto.c:
We expect cipher_name to be NUL-terminated based on its use with
the C-string format specifier %s and with other string apis like
strlen():
| printk(KERN_ERR "Error attempting to initialize key TFM "
| "cipher with name = [%s]; rc = [%d]\n",
| tmp_tfm->cipher_name, rc);
and
| int cipher_name_len = strlen(cipher_name);
In main.c:
We can remove the manual NUL-byte assignments as well as the pointers to
destinations (which I assume only existed to trim down on line length?)
in favor of directly using the destination buffer which allows the
compiler to get size information -- enabling the usage of the new
2-argument strscpy().
Note that this patch relies on the _new_ 2-argument versions of
strscpy() and strscpy_pad() introduced in Commit e6584c3964f2f ("string:
Allow 2-argument strscpy()").
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: <linux-hardening@vger.kernel.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240321-strncpy-fs-ecryptfs-crypto-c-v1-1-d78b74c214ac@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'fs/ecryptfs')
| -rw-r--r-- | fs/ecryptfs/crypto.c | 4 | ||||
| -rw-r--r-- | fs/ecryptfs/main.c | 26 |
2 files changed, 7 insertions, 23 deletions
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c index 2fe0f3af1a08..d39a1a69fecc 100644 --- a/fs/ecryptfs/crypto.c +++ b/fs/ecryptfs/crypto.c @@ -1606,9 +1606,7 @@ ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name, goto out; } mutex_init(&tmp_tfm->key_tfm_mutex); - strncpy(tmp_tfm->cipher_name, cipher_name, - ECRYPTFS_MAX_CIPHER_NAME_SIZE); - tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; + strscpy(tmp_tfm->cipher_name, cipher_name); tmp_tfm->key_size = key_size; rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm, tmp_tfm->cipher_name, diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c index 2dc927ba067f..577c56302314 100644 --- a/fs/ecryptfs/main.c +++ b/fs/ecryptfs/main.c @@ -256,11 +256,8 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options, substring_t args[MAX_OPT_ARGS]; int token; char *sig_src; - char *cipher_name_dst; char *cipher_name_src; - char *fn_cipher_name_dst; char *fn_cipher_name_src; - char *fnek_dst; char *fnek_src; char *cipher_key_bytes_src; char *fn_cipher_key_bytes_src; @@ -293,12 +290,8 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options, case ecryptfs_opt_cipher: case ecryptfs_opt_ecryptfs_cipher: cipher_name_src = args[0].from; - cipher_name_dst = - mount_crypt_stat-> - global_default_cipher_name; - strncpy(cipher_name_dst, cipher_name_src, - ECRYPTFS_MAX_CIPHER_NAME_SIZE); - cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; + strscpy(mount_crypt_stat->global_default_cipher_name, + cipher_name_src); cipher_name_set = 1; break; case ecryptfs_opt_ecryptfs_key_bytes: @@ -326,11 +319,8 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options, break; case ecryptfs_opt_fnek_sig: fnek_src = args[0].from; - fnek_dst = - mount_crypt_stat->global_default_fnek_sig; - strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX); - mount_crypt_stat->global_default_fnek_sig[ - ECRYPTFS_SIG_SIZE_HEX] = '\0'; + strscpy(mount_crypt_stat->global_default_fnek_sig, + fnek_src); rc = ecryptfs_add_global_auth_tok( mount_crypt_stat, mount_crypt_stat->global_default_fnek_sig, @@ -348,12 +338,8 @@ static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options, break; case ecryptfs_opt_fn_cipher: fn_cipher_name_src = args[0].from; - fn_cipher_name_dst = - mount_crypt_stat->global_default_fn_cipher_name; - strncpy(fn_cipher_name_dst, fn_cipher_name_src, - ECRYPTFS_MAX_CIPHER_NAME_SIZE); - mount_crypt_stat->global_default_fn_cipher_name[ - ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0'; + strscpy(mount_crypt_stat->global_default_fn_cipher_name, + fn_cipher_name_src); fn_cipher_name_set = 1; break; case ecryptfs_opt_fn_cipher_key_bytes: |