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| author |   Al Viro <viro@zeniv.linux.org.uk> | 2018-05-26 20:10:07 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2018-05-29 23:20:17 -0400 |
| commit | 1da92779e2e8f309d5aecbbed346e7f812b174e8 (patch) | |
| tree | ef7385c244e4affbec1e58b4f4cef068a80c6a4e | |
| parent | aio: fold do_io_submit() into callers (diff) | |
| download | linux-dev-1da92779e2e8f309d5aecbbed346e7f812b174e8.tar.xz linux-dev-1da92779e2e8f309d5aecbbed346e7f812b174e8.zip | |
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.c | 14 |
1 files changed, 6 insertions, 8 deletions
@@ -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; |