Commit e3286c43 authored by Liu ShuoX's avatar Liu ShuoX Committed by Jiri Slaby

pstore: Fix buffer overflow while write offset equal to buffer size

commit 017321cf upstream.

In case new offset is equal to prz->buffer_size, it won't wrap at this
time and will return old(overflow) value next time.
Signed-off-by: default avatarLiu ShuoX <shuox.liu@intel.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
parent 03a140b7
......@@ -54,7 +54,7 @@ static size_t buffer_start_add_atomic(struct persistent_ram_zone *prz, size_t a)
do {
old = atomic_read(&prz->buffer->start);
new = old + a;
while (unlikely(new > prz->buffer_size))
while (unlikely(new >= prz->buffer_size))
new -= prz->buffer_size;
} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
......@@ -91,7 +91,7 @@ static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a)
old = atomic_read(&prz->buffer->start);
new = old + a;
while (unlikely(new > prz->buffer_size))
while (unlikely(new >= prz->buffer_size))
new -= prz->buffer_size;
atomic_set(&prz->buffer->start, new);
......
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