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| author | Nathan Lynch <nathanl@linux.ibm.com> | 2023-03-07 00:33:41 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-11 17:03:31 +0300 |
| commit | 46f773f39e3094f03ea9fefc5127aa5dc612d7ee (patch) | |
| tree | e9a3785c855d8a7860bfe05780cc3ca6235edece | |
| parent | 8bcecadabb35967951cb2bedc9ee850f7dc43882 (diff) | |
| download | linux-46f773f39e3094f03ea9fefc5127aa5dc612d7ee.tar.xz | |
powerpc/rtas: use memmove for potentially overlapping buffer copy
[ Upstream commit 271208ee5e335cb1ad280d22784940daf7ddf820 ]
Using memcpy() isn't safe when buf is identical to rtas_err_buf, which
can happen during boot before slab is up. Full context which may not
be obvious from the diff:
if (altbuf) {
buf = altbuf;
} else {
buf = rtas_err_buf;
if (slab_is_available())
buf = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC);
}
if (buf)
memcpy(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX);
This was found by inspection and I'm not aware of it causing problems
in practice. It appears to have been introduced by commit
033ef338b6e0 ("powerpc: Merge rtas.c into arch/powerpc/kernel"); the
old ppc64 version of this code did not have this problem.
Use memmove() instead.
Fixes: 033ef338b6e0 ("powerpc: Merge rtas.c into arch/powerpc/kernel")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230220-rtas-queue-for-6-4-v1-2-010e4416f13f@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/powerpc/kernel/rtas.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index 767ab166933b..f8d3caad4cf3 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -421,7 +421,7 @@ static char *__fetch_rtas_last_error(char *altbuf) buf = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC); } if (buf) - memcpy(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX); + memmove(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX); } return buf; |