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author | Rusty Russell <rusty@rustcorp.com.au> | 2009-10-29 08:56:16 -0600 |
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committer | Rusty Russell <rusty@rustcorp.com.au> | 2009-10-29 08:56:17 +1030 |
commit | 65afac7d80ab3bc9f81e75eafb71eeb92a3ebdef (patch) | |
tree | 544c1e9192d8e47f1d1b1d54e36365f393ec7be0 /crypto/scatterwalk.c | |
parent | 964fe080d94db82a3268443e9b9ece4c60246414 (diff) |
param: fix lots of bugs with writing charp params from sysfs, by leaking mem.
e180a6b7759a "param: fix charp parameters set via sysfs" fixed the case
where charp parameters written via sysfs were freed, leaving drivers
accessing random memory.
Unfortunately, storing a flag in the kparam struct was a bad idea: it's
rodata so setting it causes an oops on some archs. But that's not all:
1) module_param_array() on charp doesn't work reliably, since we use an
uninitialized temporary struct kernel_param.
2) there's a fundamental race if a module uses this parameter and then
it's changed: they will still access the old, freed, memory.
The simplest fix (ie. for 2.6.32) is to never free the memory. This
prevents all these problems, at cost of a memory leak. In practice, there
are only 18 places where a charp is writable via sysfs, and all are
root-only writable.
Reported-by: Takashi Iwai <tiwai@suse.de>
Cc: Sitsofe Wheeler <sitsofe@yahoo.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
Diffstat (limited to 'crypto/scatterwalk.c')
0 files changed, 0 insertions, 0 deletions