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authorDan Carpenter <dan.carpenter@linaro.org>2023-07-25 20:03:16 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-07-27 13:07:05 -0700
commit641db40f3afe7998011bfabc726dba3e698f8196 (patch)
tree9e232cb4b05f967222113114aa8ae4b8fdd4e499 /fs/proc
parent286812b041ccc74b114cada5c10ada70a6277a20 (diff)
proc/vmcore: fix signedness bug in read_from_oldmem()
The bug is the error handling: if (tmp < nr_bytes) { "tmp" can hold negative error codes but because "nr_bytes" is type size_t the negative error codes are treated as very high positive values (success). Fix this by changing "nr_bytes" to type ssize_t. The "nr_bytes" variable is used to store values between 1 and PAGE_SIZE and they can fit in ssize_t without any issue. Link: https://lkml.kernel.org/r/b55f7eed-1c65-4adc-95d1-6c7c65a54a6e@moroto.mountain Fixes: 5d8de293c224 ("vmcore: convert copy_oldmem_page() to take an iov_iter") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Baoquan He <bhe@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/vmcore.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index cb80a7703d58..1fb213f379a5 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -132,7 +132,7 @@ ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
u64 *ppos, bool encrypted)
{
unsigned long pfn, offset;
- size_t nr_bytes;
+ ssize_t nr_bytes;
ssize_t read = 0, tmp;
int idx;