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| author | Jiri Kosina <jkosina@suse.cz> | 2016-07-08 11:38:28 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-17 09:35:28 +0100 |
| commit | f065b5f78d17fe835ad6f51f1a4f8e3e2e0efec3 (patch) | |
| tree | 9a7cb0d25dbb27557f49dfb17547d7e0ef28d1b3 /arch/x86/mm | |
| parent | 146001aeb9af927567173f1ec15eee4de6568dbe (diff) | |
| download | linux-stable-f065b5f78d17fe835ad6f51f1a4f8e3e2e0efec3.tar.gz linux-stable-f065b5f78d17fe835ad6f51f1a4f8e3e2e0efec3.tar.bz2 linux-stable-f065b5f78d17fe835ad6f51f1a4f8e3e2e0efec3.zip | |
x86/mm/pat, /dev/mem: Remove superfluous error message
commit 39380b80d72723282f0ea1d1bbf2294eae45013e upstream.
Currently it's possible for broken (or malicious) userspace to flood a
kernel log indefinitely with messages a-la
Program dmidecode tried to access /dev/mem between f0000->100000
because range_is_allowed() is case of CONFIG_STRICT_DEVMEM being turned on
dumps this information each and every time devmem_is_allowed() fails.
Reportedly userspace that is able to trigger contignuous flow of these
messages exists.
It would be possible to rate limit this message, but that'd have a
questionable value; the administrator wouldn't get information about all
the failing accessess, so then the information would be both superfluous
and incomplete at the same time :)
Returning EPERM (which is what is actually happening) is enough indication
for userspace what has happened; no need to log this particular error as
some sort of special condition.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1607081137020.24757@cbobk.fhfr.pm
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/pat.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 3f1bb4f93a5a..3146b1da6d72 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -750,11 +750,8 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size) return 1; while (cursor < to) { - if (!devmem_is_allowed(pfn)) { - pr_info("x86/PAT: Program %s tried to access /dev/mem between [mem %#010Lx-%#010Lx], PAT prevents it\n", - current->comm, from, to - 1); + if (!devmem_is_allowed(pfn)) return 0; - } cursor += PAGE_SIZE; pfn++; } |