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exec: Fix mem leak in kernel_read_file 

syzkaller report this:
BUG: memory leak
unreferenced object 0xffffc9000488d000 (size 9195520):
  comm "syz-executor.0", pid 2752, jiffies 4294787496 (age 18.757s)
  hex dump (first 32 bytes):
    ff ff ff ff ff ff ff ff a8 00 00 00 01 00 00 00  ................
    02 00 00 00 00 00 00 00 80 a1 7a c1 ff ff ff ff  ..........z.....
  backtrace:
    [<000000000863775c>] __vmalloc_node mm/vmalloc.c:1795 [inline]
    [<000000000863775c>] __vmalloc_node_flags mm/vmalloc.c:1809 [inline]
    [<000000000863775c>] vmalloc+0x8c/0xb0 mm/vmalloc.c:1831
    [<000000003f668111>] kernel_read_file+0x58f/0x7d0 fs/exec.c:924
    [<000000002385813f>] kernel_read_file_from_fd+0x49/0x80 fs/exec.c:993
    [<0000000011953ff1>] __do_sys_finit_module+0x13b/0x2a0 kernel/module.c:3895
    [<000000006f58491f>] do_syscall_64+0x147/0x600 arch/x86/entry/common.c:290
    [<00000000ee78baf4>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
    [<00000000241f889b>] 0xffffffffffffffff

It should goto 'out_free' lable to free allocated buf while kernel_read
fails.

Fixes: 39d637af5a ("vfs: forbid write access when reading a file into memory")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
YueHaibing 2019-02-19 10:10:38 +08:00 committed by Al Viro
parent fbdb440132
commit f612acfae8
1 changed files with 1 additions and 1 deletions
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2
fs/exec.c
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@ -932,7 +932,7 @@ int kernel_read_file(struct file *file, void **buf, loff_t *size,
bytes = kernel_read(file, *buf + pos, i_size - pos, &pos);
if (bytes < 0) {
ret = bytes;
goto out;
goto out_free;
}
if (bytes == 0)