diff options
| author | Alban Crequy <albancrequy@linux.microsoft.com> | 2022-11-10 09:56:13 +0100 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2022-11-11 20:44:46 +0100 |
| commit | 8678ea06852cd1f819b870c773d43df888d15d46 (patch) | |
| tree | a6accda70d5e23d0b3568f9ae322a1b4df9f918d /mm | |
| parent | selftests/bpf: Fix test_progs compilation failure in 32-bit arch (diff) | |
| download | linux-8678ea06852cd1f819b870c773d43df888d15d46.tar.xz linux-8678ea06852cd1f819b870c773d43df888d15d46.zip | |
maccess: Fix writing offset in case of fault in strncpy_from_kernel_nofault()
If a page fault occurs while copying the first byte, this function resets one
byte before dst.
As a consequence, an address could be modified and leaded to kernel crashes if
case the modified address was accessed later.
Fixes: b58294ead14c ("maccess: allow architectures to provide kernel probing directly")
Signed-off-by: Alban Crequy <albancrequy@linux.microsoft.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Francis Laniel <flaniel@linux.microsoft.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: <stable@vger.kernel.org> [5.8]
Link: https://lore.kernel.org/bpf/20221110085614.111213-2-albancrequy@linux.microsoft.com
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/maccess.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/maccess.c b/mm/maccess.c index 5f4d240f67ec..074f6b086671 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -97,7 +97,7 @@ long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count) return src - unsafe_addr; Efault: pagefault_enable(); - dst[-1] = '\0'; + dst[0] = '\0'; return -EFAULT; } |