kernel/linux.git/lib/hexdump.c, branch v4.14.304

hex2bin: fix access beyond string end

2022-05-12T10:17:06+00:00

commit e4d8a29997731b3bb14059024b24df9f784288d0 upstream. If we pass too short string to "hex2bin" (and the string size without the terminating NUL character is even), "hex2bin" reads one byte after the terminating NUL character. This patch fixes it. Note that hex_to_bin returns -1 on error and hex2bin return -EINVAL on error - so we can't just return the variable "hi" or "lo" on error. This inconsistency may be fixed in the next merge window, but for the purpose of fixing this bug, we just preserve the existing behavior and return -1 and -EINVAL. Signed-off-by: Mikulas Patocka Reviewed-by: Andy Shevchenko Fixes: b78049831ffe ("lib: add error checking to hex2bin") Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

hex2bin: make the function hex_to_bin constant-time

2022-05-12T10:17:06+00:00

commit e5be15767e7e284351853cbaba80cde8620341fb upstream. The function hex2bin is used to load cryptographic keys into device mapper targets dm-crypt and dm-integrity. It should take constant time independent on the processed data, so that concurrently running unprivileged code can't infer any information about the keys via microarchitectural convert channels. This patch changes the function hex_to_bin so that it contains no branches and no memory accesses. Note that this shouldn't cause performance degradation because the size of the new function is the same as the size of the old function (on x86-64) - and the new function causes no branch misprediction penalties. I compile-tested this function with gcc on aarch64 alpha arm hppa hppa64 i386 ia64 m68k mips32 mips64 powerpc powerpc64 riscv sh4 s390x sparc32 sparc64 x86_64 and with clang on aarch64 arm hexagon i386 mips32 mips64 powerpc powerpc64 s390x sparc32 sparc64 x86_64 to verify that there are no branches in the generated code. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

lib/hexdump.c: return -EINVAL in case of error in hex2bin()

2017-09-09T01:26:49+00:00

In some cases caller would like to use error code directly without shadowing. -EINVAL feels a rightful code to return in case of error in hex2bin(). Link: http://lkml.kernel.org/r/20170731135510.68023-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: Arnd Bergmann Cc: Rasmus Villemoes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/hexdump.c: truncate output in case of overflow

2015-11-07T01:50:42+00:00

There is a classical off-by-one error in case when we try to place, for example, 1+1 bytes as hex in the buffer of size 6. The expected result is to get an output truncated, but in the reality we get 6 bytes filed followed by terminating NUL. Change the logic how we fill the output in case of byte dumping into limited space. This will follow the snprintf() behaviour by truncating output even on half bytes. Fixes: 114fc1afb2de (hexdump: make it return number of bytes placed in buffer) Signed-off-by: Andy Shevchenko Reported-by: Aaro Koskinen Tested-by: Aaro Koskinen Cc: Al Viro Cc: Catalin Marinas Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

hexdump: fix for non-aligned buffers

2015-07-17T23:39:53+00:00

A hexdump with a buf not aligned to the groupsize causes non-naturally-aligned memory accesses. This was causing a kernel panic on the processor BlackFin BF527, when such an unaligned buffer was fed by the function ubifs_scanned_corruption in fs/ubifs/scan.c . To fix this, change accesses to the contents of the buffer so they go through get_unaligned(). This change should be harmless to unaligned- access-capable architectures, and any performance hit should be anyway dwarfed by the snprintf() processing time. Signed-off-by: Horacio Mijail Antón Quiles Cc: Andy Shevchenko Cc: David Howells Cc: Vivek Goyal Cc: Joe Perches Acked-by: Geert Uytterhoeven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

hexdump: make it return number of bytes placed in buffer

2015-02-13T02:54:15+00:00

This patch makes hexdump return the number of bytes placed in the buffer excluding trailing NUL. In the case of overflow it returns the desired amount of bytes to produce the entire dump. Thus, it mimics snprintf(). This will be useful for users that would like to repeat with a bigger buffer. [akpm@linux-foundation.org: fix printk warning] Signed-off-by: Andy Shevchenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

hexdump: do a few calculations ahead

2015-02-13T02:54:15+00:00

Instead of doing calculations in each case of different groupsize let's do them beforehand. While there, change the switch to an if-else-if construction. Signed-off-by: Andy Shevchenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

hexdump: fix ascii column for the tail of a dump

2015-02-13T02:54:14+00:00

In the current implementation we have a floating ascii column in the tail of the dump. For example, for row size equal to 16 the ascii column as in following table group size \ length 8 12 16 1 50 50 50 2 22 32 42 4 20 29 38 8 19 - 36 This patch makes it the same independently of amount of bytes dumped. The change is safe since all current users, which use ASCII part of the dump, rely on the group size equal to 1. The patch doesn't change behaviour for such group size (see the table above). Signed-off-by: Andy Shevchenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Provide a binary to hex conversion function

2014-09-16T16:36:01+00:00

Provide a function to convert a buffer of binary data into an unterminated ascii hex string representation of that data. Signed-off-by: David Howells Acked-by: Vivek Goyal

lib: introduce upper case hex ascii helpers

2013-09-20T19:38:26+00:00

To be able to use the hex ascii functions in case sensitive environments the array hex_asc_upper[] and the needed functions for hex_byte_pack_upper() are introduced. Signed-off-by: Andre Naujoks Signed-off-by: David S. Miller