mirror of
https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
synced 2024-09-21 11:53:01 +00:00
fs/proc/task_mmu.c: fix buffer overflow in add_page_map()
Recently we met quite a lot of random kernel panic issues after enabling CONFIG_PROC_PAGE_MONITOR. After debuggind we found this has something to do with following bug in pagemap: In struct pagemapread: struct pagemapread { int pos, len; pagemap_entry_t *buffer; bool v2; }; pos is number of PM_ENTRY_BYTES in buffer, but len is the size of buffer, it is a mistake to compare pos and len in add_page_map() for checking buffer is full or not, and this can lead to buffer overflow and random kernel panic issue. Correct len to be total number of PM_ENTRY_BYTES in buffer. [akpm@linux-foundation.org: document pagemapread.pos and .len units, fix PM_ENTRY_BYTES definition] Signed-off-by: Yonghua Zheng <younghua.zheng@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Git-commit: 8c8296223f3abb142be8fc31711b18a704c0e7d8) Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
This commit is contained in:
parent
d09efeaa90
commit
28e4e5d2b0
|
@ -792,14 +792,14 @@ typedef struct {
|
||||||
} pagemap_entry_t;
|
} pagemap_entry_t;
|
||||||
|
|
||||||
struct pagemapread {
|
struct pagemapread {
|
||||||
int pos, len;
|
int pos, len; /* units: PM_ENTRY_BYTES, not bytes */
|
||||||
pagemap_entry_t *buffer;
|
pagemap_entry_t *buffer;
|
||||||
};
|
};
|
||||||
|
|
||||||
#define PAGEMAP_WALK_SIZE (PMD_SIZE)
|
#define PAGEMAP_WALK_SIZE (PMD_SIZE)
|
||||||
#define PAGEMAP_WALK_MASK (PMD_MASK)
|
#define PAGEMAP_WALK_MASK (PMD_MASK)
|
||||||
|
|
||||||
#define PM_ENTRY_BYTES sizeof(u64)
|
#define PM_ENTRY_BYTES sizeof(pagemap_entry_t)
|
||||||
#define PM_STATUS_BITS 3
|
#define PM_STATUS_BITS 3
|
||||||
#define PM_STATUS_OFFSET (64 - PM_STATUS_BITS)
|
#define PM_STATUS_OFFSET (64 - PM_STATUS_BITS)
|
||||||
#define PM_STATUS_MASK (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
|
#define PM_STATUS_MASK (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
|
||||||
|
@ -1038,8 +1038,8 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
|
||||||
if (!count)
|
if (!count)
|
||||||
goto out_task;
|
goto out_task;
|
||||||
|
|
||||||
pm.len = PM_ENTRY_BYTES * (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
|
pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
|
||||||
pm.buffer = kmalloc(pm.len, GFP_TEMPORARY);
|
pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY);
|
||||||
ret = -ENOMEM;
|
ret = -ENOMEM;
|
||||||
if (!pm.buffer)
|
if (!pm.buffer)
|
||||||
goto out_task;
|
goto out_task;
|
||||||
|
|
Loading…
Reference in a new issue