linux-stable.git/lib/string_helpers.c, branch linux-5.15.y

lib: string_helpers: silence snprintf() output truncation warning

2024-12-14T18:51:18+00:00

commit a508ef4b1dcc82227edc594ffae583874dd425d7 upstream.

The output of ".%03u" with the unsigned int in range [0, 4294966295] may
get truncated if the target buffer is not 12 bytes. This can't really
happen here as the 'remainder' variable cannot exceed 999 but the
compiler doesn't know it. To make it happy just increase the buffer to
where the warning goes away.

Fixes: 3c9f3681d0b4 ("[SCSI] lib: add generic helper to print sizes rounded to the correct SI range")
Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Andy Shevchenko 
Cc: James E.J. Bottomley 
Cc: Kees Cook 
Cc: stable@vger.kernel.org
Signed-off-by: Andrew Morton 
Link: https://lore.kernel.org/r/20241101205453.9353-1-brgl@bgdev.pl
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman

string: uninline memcpy_and_pad

2021-11-21T12:44:12+00:00

commit 5c4e0a21fae877a7ef89be6dcc6263ec672372b8 upstream.

When building m68k:allmodconfig, recent versions of gcc generate the
following error if the length of UTS_RELEASE is less than 8 bytes.

  In function 'memcpy_and_pad',
    inlined from 'nvmet_execute_disc_identify' at
      drivers/nvme/target/discovery.c:268:2: arch/m68k/include/asm/string.h:72:25: error:
	'__builtin_memcpy' reading 8 bytes from a region of size 7

Discussions around the problem suggest that this only happens if an
architecture does not provide strlen(), if -ffreestanding is provided as
compiler option, and if CONFIG_FORTIFY_SOURCE=n. All of this is the case
for m68k. The exact reasons are unknown, but seem to be related to the
ability of the compiler to evaluate the return value of strlen() and
the resulting execution flow in memcpy_and_pad(). It would be possible
to work around the problem by using sizeof(UTS_RELEASE) instead of
strlen(UTS_RELEASE), but that would only postpone the problem until the
function is called in a similar way. Uninline memcpy_and_pad() instead
to solve the problem for good.

Suggested-by: Linus Torvalds 
Reviewed-by: Geert Uytterhoeven 
Acked-by: Andy Shevchenko 
Signed-off-by: Guenter Roeck 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

string_helpers: Escape double quotes in escape_special

2021-07-19T09:39:28+00:00

From an abstract point of view, escape_special's counterpart,
unescape_special, already handles the unescaping of blackslashed double
quote sequences.

As a more practical example, printk indexing is an example case where
this is already practically useful. Compare an example with
`ESCAPE_SPECIAL | ESCAPE_SPACE`, with quotes not escaped:

    [root@ktst ~]# grep drivers/pci/pci-stub.c:69 /sys/kernel/debug/printk/index/vmlinux
    <4> drivers/pci/pci-stub.c:69 pci_stub_init "pci-stub: invalid ID string "%s"\n"

...and the same after this patch:

    [root@ktst ~]# grep drivers/pci/pci-stub.c:69 /sys/kernel/debug/printk/index/vmlinux
    <4> drivers/pci/pci-stub.c:69 pci_stub_init "pci-stub: invalid ID string \"%s\"\n"

One can of course, alternatively, use ESCAPE_APPEND with a quote in
@only, but without this patch quotes are coerced into hex or octal which
can hurt readability quite significantly.

I've checked uses of ESCAPE_SPECIAL and %pE across the codebase, and I'm
pretty confident that this shouldn't affect any stable interfaces.

Signed-off-by: Chris Down 
Reviewed-by: Andy Shevchenko 
Reviewed-by: Petr Mladek 
Cc: Rasmus Villemoes 
Acked-by: Andy Shevchenko 
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/af144c5b75e41ce417386253ba2694456bc04118.1623775748.git.chris@chrisdown.name

seq_file: drop unused *_escape_mem_ascii()

2021-07-01T18:06:05+00:00

There are no more users of the seq_escape_mem_ascii() followed by
string_escape_mem_ascii().

Remove them for good.

Link: https://lkml.kernel.org/r/20210504180819.73127-16-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Cc: Alexander Viro 
Cc: Chuck Lever 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/string_helpers: allow to append additional characters to be escaped

2021-07-01T18:06:04+00:00

Introduce a new flag to append additional characters, passed in 'only'
parameter, to be escaped if they fall in the corresponding class.

Link: https://lkml.kernel.org/r/20210504180819.73127-7-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Cc: Alexander Viro 
Cc: Chuck Lever 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/string_helpers: introduce ESCAPE_NAP to escape non-ASCII and non-printable

2021-07-01T18:06:04+00:00

Some users may want to have an ASCII based filter for printable only
characters, provided by conjunction of isascii() and isprint() functions.

Here is the addition of a such.

Link: https://lkml.kernel.org/r/20210504180819.73127-6-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Cc: Alexander Viro 
Cc: Chuck Lever 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/string_helpers: introduce ESCAPE_NA for escaping non-ASCII

2021-07-01T18:06:04+00:00

Some users may want to have an ASCII based filter, provided by isascii()
function.  Here is the addition of a such.

Link: https://lkml.kernel.org/r/20210504180819.73127-5-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Cc: Alexander Viro 
Cc: Chuck Lever 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/string_helpers: drop indentation level in string_escape_mem()

2021-07-01T18:06:04+00:00

The only one conditional is left on the upper level, move the rest to the
same level and drop indentation level.  No functional changes.

Link: https://lkml.kernel.org/r/20210504180819.73127-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Cc: Alexander Viro 
Cc: Chuck Lever 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib/string_helpers: move ESCAPE_NP check inside 'else' branch in a loop

2021-07-01T18:06:04+00:00

Refactor code to have better readability by moving ESCAPE_NP handling
inside 'else' branch in the loop.

No functional change intended.

Link: https://lkml.kernel.org/r/20210504180819.73127-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko 
Cc: Alexander Viro 
Cc: Chuck Lever 
Cc: "J. Bruce Fields" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib: string_helpers: provide kfree_strarray()

2020-09-30T08:50:30+00:00

There's a common pattern of dynamically allocating an array of char
pointers and then also dynamically allocating each string in this
array. Provide a helper for freeing such a string array with one call.

Signed-off-by: Bartosz Golaszewski 
Reviewed-by: Andy Shevchenko