On Fri, May 18, 2012 at 3:24 PM, Anton Vorontsov anton.vorontsov@linaro.org wrote:
Otherwise, unlinked file will reappear on the next boot.
Reported-by: Kees Cook keescook@chromium.org Signed-off-by: Anton Vorontsov anton.vorontsov@linaro.org
fs/pstore/ram.c | 1 + fs/pstore/ram_core.c | 6 ++++++ include/linux/pstore_ram.h | 1 + 3 files changed, 8 insertions(+)
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 3a7724b..43d9727 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -186,6 +186,7 @@ static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, return -EINVAL;
persistent_ram_free_old(cxt->przs[id]);
- persistent_ram_zap(cxt->przs[id]);
return 0; } diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c index dff5127..28b6d7f 100644 --- a/fs/pstore/ram_core.c +++ b/fs/pstore/ram_core.c @@ -336,6 +336,12 @@ void persistent_ram_free_old(struct persistent_ram_zone *prz) prz->old_log_size = 0; }
+void persistent_ram_zap(struct persistent_ram_zone *prz) +{
- atomic_set(&prz->buffer->size, 0);
There are a couple places in the ringbuffer code that assume that the data is located in the buffer in the range [0, size). It may start anywhere in that range and wrap, but address 0 in the buffer always contains data. Resetting size to 0 but leaving start non-zero may result in no data at address zero, and will cause problems in at least persistent_ram_save_old, persistent_ram_ecc_old, persistent_ram_copy_old, and the detection code in persistent_ram_post_init. These would all need to be fixed to support the dual-metadata ringbuffer option I mentioned in response to patch 3, but if you don't like that idea then just clear start here.
- persistent_ram_update_header_ecc(prz);
+}
static void *persistent_ram_vmap(phys_addr_t start, size_t size) { struct page **pages; diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h index 07d59b7..085199e 100644 --- a/include/linux/pstore_ram.h +++ b/include/linux/pstore_ram.h @@ -69,6 +69,7 @@ struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start, size_t size, bool ecc); void persistent_ram_free(struct persistent_ram_zone *prz); +void persistent_ram_zap(struct persistent_ram_zone *prz); struct persistent_ram_zone *persistent_ram_init_ringbuffer(struct device *dev, bool ecc);
-- 1.7.9.2