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27 March 2024, 02:37:15 UTC
Revision 955eff5acc8b8cd1c7d4eec0229c35eaabe013db authored by Nick Piggin on 20 February 2007, 21:58:08 UTC, committed by Linus Torvalds on 21 February 2007, 01:10:15 UTC 
[PATCH] fs: fix libfs data leak
 
simple_prepare_write leaks uninitialised kernel data.  This happens because
the it leaves an uninitialised "hole" over the part of the page that the
write is expected to go to.  This is fine, but it then marks the page
uptodate, which means a concurrent read can come in and copy the
uninitialised memory into userspace before it written to.

Fix it by simply marking it uptodate in simple_commit_write instead, after
the hole has been filled in.  This could theoretically break an fs that
uses simple_prepare_write and not simple_commit_write, and that relies on
the incorrect simple_prepare_write behaviour.  Luckily, none of those
exists in the tree.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent c066332
History
Tip revision: 955eff5acc8b8cd1c7d4eec0229c35eaabe013db authored by Nick Piggin on 20 February 2007, 21:58:08 UTC
[PATCH] fs: fix libfs data leak
Tip revision: 955eff5
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include
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usr
.gitignore -rw-r--r-- 572 bytes
.mailmap -rw-r--r-- 3.5 KB
COPYING -rw-r--r-- 18.3 KB
CREDITS -rw-r--r-- 88.9 KB
Kbuild -rw-r--r-- 1.2 KB
MAINTAINERS -rw-r--r-- 81.9 KB
Makefile -rw-r--r-- 49.1 KB
README -rw-r--r-- 16.5 KB
REPORTING-BUGS -rw-r--r-- 3.0 KB

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