From d6f3385b1a3f2fba8e14d6794bece1dcdd9e479e Mon Sep 17 00:00:00 2001 From: Aleksandr Nogikh Date: Wed, 12 Jan 2022 14:40:51 +0000 Subject: all: add syz_clone() and syz_clone3() pseudo calls As was pointed out in #2921, the current approach of limiting the number of pids per process does not work on all Linux-based kernels. We could just treat fork, clone and clone3 in a special way (e.g. exit on a zero return). However, in that case we also need to sanitize the arguments for clone and clone3 - if CLONE_VM is passed and stack is 0, the forked child processes (threads) will become nearly unindentifiable and will corrupt syz-executor's memory. While we could sanitize clone's arguments, we cannot do so for clone3 - nothing can guarantee that they will not be changed concurrently. Instead of calling those syscalls directly, introduce a special pseudo syscall syz_clone3. It copies and sanitizes the arguments and then executes clone3 (or fork, if we're on an older kernel) in such a way so as to prevent fork bombs from happening. Also introduce syz_clone() to still be able to fuzz it on older systems. --- sys/linux/test/syz_clone3 | 3 +++ 1 file changed, 3 insertions(+) create mode 100644 sys/linux/test/syz_clone3 (limited to 'sys/linux/test/syz_clone3') diff --git a/sys/linux/test/syz_clone3 b/sys/linux/test/syz_clone3 new file mode 100644 index 000000000..5539d7f86 --- /dev/null +++ b/sys/linux/test/syz_clone3 @@ -0,0 +1,3 @@ +# requires: arch=amd64 + +syz_clone3(&AUTO={0x11, 0x0, 0x0, 0x0, {0x11}, 0x0, 0x0, 0x0, 0x0, 0x0, {0x0}}, AUTO) -- cgit mrf-deployment