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| author | Anton Vorontsov <anton.vorontsov@linaro.org> | 2012-06-19 06:15:53 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-06-21 03:15:22 +0400 |
| commit | 1e6a9e56252399ae8c143f2327b4bb8cd289c3d5 (patch) | |
| tree | e4dfb2629ec406052214197f8610ec5fbb39c724 /fs/pstore | |
| parent | beeb94321a7a6d493b4a06ff0cd771f09f41c35e (diff) | |
| download | linux-1e6a9e56252399ae8c143f2327b4bb8cd289c3d5.tar.xz | |
pstore/ram_core: Better ECC size checking
- Instead of exploiting unsigned overflows (which doesn't work for all
sizes), use straightforward checking for ECC total size not exceeding
initial buffer size;
- Printing overflowed buffer_size is not informative. Instead, print
ecc_size and buffer_size;
- No need for buffer_size argument in persistent_ram_init_ecc(),
we can address prz->buffer_size directly.
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/pstore')
| -rw-r--r-- | fs/pstore/ram_core.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index f62ebf2dfed7..a5a7b13d358c 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -171,12 +171,12 @@ static void persistent_ram_ecc_old(struct persistent_ram_zone *prz) } } -static int persistent_ram_init_ecc(struct persistent_ram_zone *prz, - size_t buffer_size) +static int persistent_ram_init_ecc(struct persistent_ram_zone *prz) { int numerr; struct persistent_ram_buffer *buffer = prz->buffer; int ecc_blocks; + size_t ecc_total; if (!prz->ecc) return 0; @@ -187,14 +187,14 @@ static int persistent_ram_init_ecc(struct persistent_ram_zone *prz, prz->ecc_poly = 0x11d; ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size); - prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size; - - if (prz->buffer_size > buffer_size) { - pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n", - buffer_size, prz->buffer_size); + ecc_total = (ecc_blocks + 1) * prz->ecc_size; + if (ecc_total >= prz->buffer_size) { + pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n", + __func__, prz->ecc_size, ecc_total, prz->buffer_size); return -EINVAL; } + prz->buffer_size -= ecc_total; prz->par_buffer = buffer->data + prz->buffer_size; prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size; @@ -397,7 +397,7 @@ static int __devinit persistent_ram_post_init(struct persistent_ram_zone *prz, prz->ecc = ecc; - ret = persistent_ram_init_ecc(prz, prz->buffer_size); + ret = persistent_ram_init_ecc(prz); if (ret) return ret; |