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authorAnton Vorontsov <anton.vorontsov@linaro.org>2012-06-18 19:15:53 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-06-20 16:15:22 -0700
commit1e6a9e56252399ae8c143f2327b4bb8cd289c3d5 (patch)
treee4dfb2629ec406052214197f8610ec5fbb39c724 /fs/pstore/ram_core.c
parentbeeb94321a7a6d493b4a06ff0cd771f09f41c35e (diff)
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/ram_core.c')
-rw-r--r--fs/pstore/ram_core.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index f62ebf2dfed..a5a7b13d358 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;