bugfix: passthrough: refect CFileHandle struct #106
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xuejun-xj
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jiangliu,
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wllenyj
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Feb 23, 2023
src/passthrough/file_handle.rs
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| #[repr(C)] | ||
| pub struct MockCFileHandle { |
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Mock feels like testing code.
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Thanks, @wllenyj! I have renamed it as CFileHandleInner.
src/passthrough/file_handle.rs
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| // File identifier (sized by caller) [out] | ||
| f_handle: *mut libc::c_char, | ||
| f_handle: Vec<u8>, |
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| f_handle: Vec<u8>, | |
| type CFileHandle = FamStructWrapper<CFileHandleInner>; | |
| pub struct CFileHandlerInner { | |
| handle_bytes: u32, | |
| handle_type: i32, | |
| f_handle: __IncompleteArrayField<libc::c_char> | |
| } |
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Thanks, @wllenyj! As CFileHandle needs to implement some traits, like Ord, PartialOrd, I use a CFileHandleWrapper instead, which is used as a memory of CFileHandle struct.
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Previously, CFileHandle uses a *mut libc::c_char to transfer data between user space and kernel space. The system call "name_to_handle_at" will return the data with "copy_to_user". This may cause a bug because the memory layout of CFileHandle fields may be noncontinuous with the dynamically-sized array's. Therefore, the "copy_to_user" may destroy the stack. This is reproduced on aarch64 only when using "opt-level=3" to compile. This commit refectors the CFileHandle struct with FarmStruct trait to ensure the memory layout to be continuous. The trait enables struct to own a dynamically-sized array at the end of the struct like zero-array in C language. We refector the related implementation so that "copy_to_user" won't write outside the CFileHandle and destroy the user stack. Besides, add some units and fix clippy warnings. Signed-off-by: xuejun-xj <[email protected]>
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jiangliu
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Feb 24, 2023
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Previously, CFileHandle uses a *mut libc::c_char to transfer data between user space and kernel space. The system call "name_to_handle_at" will return the data with "copy_to_user". This may cause a bug because the memory layout of CFileHandle fields may be noncontinuous with the dynamically-sized array's. Therefore, the "copy_to_user" may destroy the stack. This is reproduced on aarch64 only when using "opt-level=3" to compile.
This commit refectors the CFileHandle struct with FarmStruct trait to ensure the memory layout to be continuous. The trait enables struct to own a dynamically-sized array at the end of the struct like zero-array in C language. We refector the related implementation so that "copy_to_user" won't write outside the CFileHandle and destroy the user stack.
Besides, add some units and fix clippy warnings.