user/sven/linux.git/fs/binfmt_flat.c, branch v4.9.293

fs/binfmt_flat.c: make load_flat_shared_library() work

2019-07-10T07:55:38Z

commit 867bfa4a5fcee66f2b25639acae718e8b28b25a5 upstream. load_flat_shared_library() is broken: It only calls load_flat_file() if prepare_binprm() returns zero, but prepare_binprm() returns the number of bytes read - so this only happens if the file is empty. Instead, call into load_flat_file() if the number of bytes read is non-negative. (Even if the number of bytes is zero - in that case, load_flat_file() will see nullbytes and return a nice -ENOEXEC.) In addition, remove the code related to bprm creds and stop using prepare_binprm() - this code is loading a library, not a main executable, and it only actually uses the members "buf", "file" and "filename" of the linux_binprm struct. Instead, call kernel_read() directly. Link: http://lkml.kernel.org/r/20190524201817.16509-1-jannh@google.com Fixes: 287980e49ffc ("remove lots of IS_ERR_VALUE abuses") Signed-off-by: Jann Horn Cc: Alexander Viro Cc: Kees Cook Cc: Nicolas Pitre Cc: Arnd Bergmann Cc: Geert Uytterhoeven Cc: Russell King Cc: Greg Ungerer Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

binfmt_flat: allow compressed flat binary format to work on MMU systems

2016-07-28T03:29:12Z

Let's take the simple and obvious approach by decompressing the binary into a kernel buffer and then copying it to user space. Those who are looking for top performance on an MMU system are unlikely to choose this executable format anyway. Signed-off-by: Nicolas Pitre Reviewed-by: Greg Ungerer Signed-off-by: Greg Ungerer

binfmt_flat: add MMU-specific support

2016-07-28T03:29:12Z

Not much else to do at this point except for the different stack setups. Signed-off-by: Nicolas Pitre Reviewed-by: Greg Ungerer Signed-off-by: Greg Ungerer

binfmt_flat: update libraries' data segment pointer with userspace accessors

2016-07-28T03:29:11Z

This is needed on systems with a MMU. This also gets rid of the strangest C code I've seen lateli i.e. an integer indexed with a pointer value within square brackets. That really looked backwards. Signed-off-by: Nicolas Pitre Reviewed-by: Greg Ungerer Signed-off-by: Greg Ungerer

binfmt_flat: use clear_user() rather than memset() to clear .bss

2016-07-28T03:29:11Z

This is needed on systems with a MMU. Signed-off-by: Nicolas Pitre Reviewed-by: Greg Ungerer Signed-off-by: Greg Ungerer

binfmt_flat: use proper user space accessors with old relocs code

2016-07-28T03:28:58Z

Signed-off-by: Nicolas Pitre Reviewed-by: Greg Ungerer Signed-off-by: Greg Ungerer

binfmt_flat: use proper user space accessors with relocs processing code

2016-07-25T06:52:06Z

Relocs are fixed up in place in user space memory. The appropriate accessors are required for this code to work with an active MMU. The architecture specific handlers flat_get_addr_from_rp() and flat_put_addr_at_rp() for ARM and M68K are adjusted with separate patches. SuperH and Xtensa are left out as they doesn't implement __get_user_unaligned() and __put_user_unaligned() yet. The other architectures that use BFLT don't have any MMU. Signed-off-by: Nicolas Pitre Reviewed-by: Greg Ungerer Signed-off-by: Greg Ungerer

binfmt_flat: clean up create_flat_tables() and stack accesses

2016-07-25T06:52:01Z

In addition to better code clarity, this brings proper usage of user memory accessors everywhere the stack is touched. This is essential for making this work on MMU systems. Signed-off-by: Nicolas Pitre Reviewed-by: Greg Ungerer Signed-off-by: Greg Ungerer

binfmt_flat: use generic transfer_args_to_stack()

2016-07-25T06:51:55Z

This gets rid of the rather ugly, open coded and suboptimal copy code. Signed-off-by: Nicolas Pitre Reviewed-by: Greg Ungerer Signed-off-by: Greg Ungerer

binfmt_flat: prevent kernel dammage from corrupted executable headers

2016-07-25T06:51:42Z

Signed-off-by: Nicolas Pitre Signed-off-by: Greg Ungerer