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authorAl Viro <viro@zeniv.linux.org.uk>2018-05-26 20:10:07 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2018-05-29 23:20:17 -0400
commit1da92779e2e8f309d5aecbbed346e7f812b174e8 (patch)
treeef7385c244e4affbec1e58b4f4cef068a80c6a4e
parent67ba049f94ebe49ed557e590dd243b6db45c9aff (diff)
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aio: sanitize the limit checking in io_submit(2)
as it is, the logics in native io_submit(2) is "if asked for more than LONG_MAX/sizeof(pointer) iocbs to submit, don't bother with more than LONG_MAX/sizeof(pointer)" (i.e. 512M requests on 32bit and 1E requests on 64bit) while compat io_submit(2) goes with "stop after the first PAGE_SIZE/sizeof(pointer) iocbs", i.e. 1K or so. Which is * inconsistent * *way* too much in native case * possibly too little in compat one and * wrong anyway, since the natural point where we ought to stop bothering is ctx->nr_events Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/aio.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/fs/aio.c b/fs/aio.c
index da859574c953..b850e92ee0d5 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1841,15 +1841,15 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
if (unlikely(nr < 0))
return -EINVAL;
- if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
- nr = LONG_MAX/sizeof(*iocbpp);
-
ctx = lookup_ioctx(ctx_id);
if (unlikely(!ctx)) {
pr_debug("EINVAL: invalid context id\n");
return -EINVAL;
}
+ if (nr > ctx->nr_events)
+ nr = ctx->nr_events;
+
blk_start_plug(&plug);
for (i = 0; i < nr; i++) {
struct iocb __user *user_iocb;
@@ -1870,8 +1870,6 @@ SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
}
#ifdef CONFIG_COMPAT
-#define MAX_AIO_SUBMITS (PAGE_SIZE/sizeof(struct iocb *))
-
COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
int, nr, compat_uptr_t __user *, iocbpp)
{
@@ -1883,15 +1881,15 @@ COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
if (unlikely(nr < 0))
return -EINVAL;
- if (nr > MAX_AIO_SUBMITS)
- nr = MAX_AIO_SUBMITS;
-
ctx = lookup_ioctx(ctx_id);
if (unlikely(!ctx)) {
pr_debug("EINVAL: invalid context id\n");
return -EINVAL;
}
+ if (nr > ctx->nr_events)
+ nr = ctx->nr_events;
+
blk_start_plug(&plug);
for (i = 0; i < nr; i++) {
compat_uptr_t user_iocb;