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authorJustin Stitt <justinstitt@google.com>2023-09-19 08:30:35 +0300
committerJens Axboe <axboe@kernel.dk>2023-10-04 03:23:02 +0300
commite1f2760ba3478fa3f8c48db8e91fbe3df8bea2f8 (patch)
tree14e57e3e8031ce4eec867b5a9619ec39987626ba /drivers/block
parent114b0ff62a6510eb218660cb4925b4c4a01cdd84 (diff)
downloadlinux-e1f2760ba3478fa3f8c48db8e91fbe3df8bea2f8.tar.xz
null_blk: replace strncpy with strscpy
`strncpy` is deprecated for use on NUL-terminated destination strings [1]. We should favor a more robust and less ambiguous interface. We expect that both `nullb->disk_name` and `disk->disk_name` be NUL-terminated: | snprintf(nullb->disk_name, sizeof(nullb->disk_name), | "%s", config_item_name(&dev->group.cg_item)); ... | pr_info("disk %s created\n", nullb->disk_name); It seems like NUL-padding may be required due to __assign_disk_name() utilizing a memcpy as opposed to a `str*cpy` api. | static inline void __assign_disk_name(char *name, struct gendisk *disk) | { | if (disk) | memcpy(name, disk->disk_name, DISK_NAME_LEN); | else | memset(name, 0, DISK_NAME_LEN); | } Then we go and print it with `__print_disk_name` which wraps `nullb_trace_disk_name()`. | #define __print_disk_name(name) nullb_trace_disk_name(p, name) This function obviously expects a NUL-terminated string. | const char *nullb_trace_disk_name(struct trace_seq *p, char *name) | { | const char *ret = trace_seq_buffer_ptr(p); | | if (name && *name) | trace_seq_printf(p, "disk=%s, ", name); | trace_seq_putc(p, 0); | | return ret; | } >From the above, we need both 1) a NUL-terminated string and 2) a NUL-padded string. So, let's use strscpy_pad() as per Kees' suggestion from v1. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Cc: Kees Cook <keescook@chromium.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Justin Stitt <justinstitt@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20230919-strncpy-drivers-block-null_blk-main-c-v3-1-10cf0a87a2c3@google.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/null_blk/main.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 79d6cd3c3d41..22a3cf7f32e2 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1966,7 +1966,7 @@ static int null_gendisk_register(struct nullb *nullb)
else
disk->fops = &null_bio_ops;
disk->private_data = nullb;
- strncpy(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
+ strscpy_pad(disk->disk_name, nullb->disk_name, DISK_NAME_LEN);
if (nullb->dev->zoned) {
int ret = null_register_zoned_dev(nullb);