efi: cper: fix snprintf() use in cper_dimm_err_location()

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[ Upstream commit 942859d969 ]

snprintf() should be given the full buffer size, not one less. And it
guarantees nul-termination, so doing it manually afterwards is
pointless.

It's even potentially harmful (though probably not in practice because
CPER_REC_LEN is 256), due to the "return how much would have been
written had the buffer been big enough" semantics. I.e., if the bank
and/or device strings are long enough that the "DIMM location ..."
output gets truncated, writing to msg[n] is a buffer overflow.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Fixes: 3760cd2040 ("CPER: Adjust code flow of some functions")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

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Rasmus Villemoes 2021-04-21 21:46:36 +02:00 • committed by Greg Kroah-Hartman

parent 951f8ef71d

commit 8d27efbb0e

1 changed files with 1 additions and 3 deletions

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drivers/firmware/efi/cper.c

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