nshlib/nsh_fscmds.c: Allocate a PATH_MAX sized buffer for unlink_recursive #3222
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…rsive This fixes heap corruption when deleting a folder containing other folders or files. The issue appeared at commit 131d50a, which removed the stack-based temporary buffer. unlink_recursive requires that the path is provided in PATH_MAX sized buffer. It concatenates sub-folder or file names to the same buffer. nsh_getfullpath just allocates a buffer using strdup, so there is no room for concatenating more data to it. To keep the stack usage smaller, instead of reverting the breaking commit, allocate the temporary buffer with lib_get_pathbuffer instead. Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
cederom
approved these changes
Nov 25, 2025
linguini1
approved these changes
Nov 26, 2025
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Summary
This fixes heap corruption when deleting a folder containing other folders or files. The issue appeared at commit 131d50a, which removed the stack-based temporary buffer.
unlink_recursive requires that the path is provided in PATH_MAX sized buffer. It concatenates sub-folder or file names to the same buffer.
nsh_getfullpath just allocates a buffer using strdup, so there is no room for concatenating more data to it.
To keep the stack usage smaller, instead of reverting the breaking commit, allocate the temporary buffer with lib_get_pathbuffer instead.
Impact
Fixes "rm -rf " in nsh.
Testing
Tested on imx9 hardware in CONFIG_BUILD_FLAT after mounting sdcard on /fs/microsd and executing the following sequence:
With this patch, the sequence above can be executed many times.
Without the fix, the system crashes: