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| author | Justin Stitt <justinstitt@google.com> | 2023-10-19 23:28:32 +0000 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2023-10-20 19:50:40 +0200 |
| commit | 50cbdaf1b93a2cc89d7712feafa76cf1b2f28adc (patch) | |
| tree | 409de3814d9f59e628ea93b1053addd2328307ae /drivers/pnp | |
| parent | eda1a74655ea282fcac56af5ca18ff1394542e29 (diff) | |
| download | linux-50cbdaf1b93a2cc89d7712feafa76cf1b2f28adc.tar.gz linux-50cbdaf1b93a2cc89d7712feafa76cf1b2f28adc.tar.bz2 linux-50cbdaf1b93a2cc89d7712feafa76cf1b2f28adc.zip | |
PNP: replace deprecated strncpy() with memcpy()
strncpy() is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous
interfaces.
After having precisely calculated the lengths and ensuring we don't
overflow the buffer, this really decays to just a memcpy. Let's not use
a C string api as it makes the intention of the code confusing.
It'd be nice to use strscpy() in this case (as we clearly want
NUL-termination) because it'd clean up the code a bit. However, I don't
quite know enough about what is going on here to justify a drop-in
replacement -- too much bit magic and why (PNP_NAME_LEN - 2)? I'm afraid
using strscpy() may result in copying too many or too few bytes into our
dev->name buffer resulting in different behavior. At least using
memcpy() we can ensure the behavior is exactly the same.
Side note:
NUL-padding is not required because insert_device() calls
pnpbios_parse_data_stream() with a zero-allocated `dev`:
299 | static int __init insert_device(struct pnp_bios_node *node) {
...
312 | dev = pnp_alloc_dev(&pnpbios_protocol, node->handle, id);
...
316 | pnpbios_parse_data_stream(dev, node);
then pnpbios_parse_data_stream() calls pnpbios_parse_compatible_ids().
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
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/pnp')
| -rw-r--r-- | drivers/pnp/pnpbios/rsparser.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/pnp/pnpbios/rsparser.c b/drivers/pnp/pnpbios/rsparser.c index 2f31b212b1a5..70af7821d3fa 100644 --- a/drivers/pnp/pnpbios/rsparser.c +++ b/drivers/pnp/pnpbios/rsparser.c @@ -454,8 +454,8 @@ static unsigned char *pnpbios_parse_compatible_ids(unsigned char *p, switch (tag) { case LARGE_TAG_ANSISTR: - strncpy(dev->name, p + 3, - len >= PNP_NAME_LEN ? PNP_NAME_LEN - 2 : len); + memcpy(dev->name, p + 3, + len >= PNP_NAME_LEN ? PNP_NAME_LEN - 2 : len); dev->name[len >= PNP_NAME_LEN ? PNP_NAME_LEN - 1 : len] = '\0'; break; |