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Petersen" Cc: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Justin Stitt strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. We expect p_buf to be NUL-terminated based on the callsites using these transport_dump_* methods because they use the destination buf with C-string APIs like strlen() and sprintf(). memset(buf, 0, VPD_TMP_BUF_SIZE); \ transport_dump_vpd_ident_type(vpd, buf, VPD_TMP_BUF_SIZE); \ if (len + strlen(buf) >= PAGE_SIZE) \ break; \ len += sprintf(page+len, "%s", buf); \ We also do not require the NUL-padding behavior that strncpy() provides because we are manually setting the entire buffer to NUL, rendering any future padding redundant. Let's use strscpy() as it guarantees NUL-termination and doesn't NUL-pad ( and isn't deprecated :>] ). Note that we can't use the more idiomatic strscpy() usage of strscpy(dest, src, sizeof(dest)) because the size of the destination buffer is not known to the compiler. We also can't use the new 2-arg version of strscpy() from 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 Reviewed-by: Kees Cook --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/target/target_core_transport.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- base-commit: bf3a69c6861ff4dc7892d895c87074af7bc1c400 change-id: 20240318-strncpy-drivers-target-target_core_transport-c-1950554ec04e Best regards, -- Justin Stitt diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 73d0d6133ac8..3311eb87df6d 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1112,7 +1112,7 @@ void transport_dump_vpd_proto_id( } if (p_buf) - strncpy(p_buf, buf, p_buf_len); + strscpy(p_buf, buf, p_buf_len); else pr_debug("%s", buf); } @@ -1162,7 +1162,7 @@ int transport_dump_vpd_assoc( } if (p_buf) - strncpy(p_buf, buf, p_buf_len); + strscpy(p_buf, buf, p_buf_len); else pr_debug("%s", buf); @@ -1222,7 +1222,7 @@ int transport_dump_vpd_ident_type( if (p_buf) { if (p_buf_len < strlen(buf)+1) return -EINVAL; - strncpy(p_buf, buf, p_buf_len); + strscpy(p_buf, buf, p_buf_len); } else { pr_debug("%s", buf); } @@ -1276,7 +1276,7 @@ int transport_dump_vpd_ident( } if (p_buf) - strncpy(p_buf, buf, p_buf_len); + strscpy(p_buf, buf, p_buf_len); else pr_debug("%s", buf);