Fix Integer overflow in binary CPIO handler#5089
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sectroyer wants to merge 1 commit intoMidnightCommander:masterfrom
Open
Fix Integer overflow in binary CPIO handler#5089sectroyer wants to merge 1 commit intoMidnightCommander:masterfrom
sectroyer wants to merge 1 commit intoMidnightCommander:masterfrom
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area: vfs
mc-worker
reviewed
Apr 16, 2026
| // case? | ||
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| inode->linkname = g_malloc (st->st_size + 1); | ||
| if (st->st_size < 0 || (gsize) st->st_size >= G_MAXSIZE) |
Contributor
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Why do you reduce off_t to gsize? I think, sizeof (off_t) >= sizeof (gsize), so the correct way is
st->st_size >= (off_t) G_MAXSIZE
| #endif | ||
| st.st_size = ((off_t) u.buf.c_filesizes[0] << 16) | u.buf.c_filesizes[1]; | ||
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| if (st.st_size < 0 || st.st_size > MC_MAXPATHLEN) |
Contributor
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Why do you compare file size with path length? It is correct for link not for regular file,
| u.st.st_size = hd.c_filesize; | ||
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| if (u.st.st_size < 0 || u.st.st_size > MC_MAXPATHLEN) | ||
| { |
Author
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You are completely right. I have update the PR w newer fix.
…ndler Three changes addressing reviewer feedback: - cpio_create_entry: fix cast direction in the bounds check — compare against (off_t) G_MAXSIZE rather than casting st_size to gsize. Also add the MC_MAXPATHLEN upper bound here, co-located with the g_malloc call and applied only in the symlink code path where st_size is used as a path length. - cpio_read_bin_head: check only st_size < 0 (catches the signed integer overflow root cause). Remove the > MC_MAXPATHLEN bound which was too restrictive for non-symlink entries processed by this general-purpose function. - cpio_read_crc_head: same as cpio_read_bin_head. Signed-off-by: Michał Majchrowicz <sectroyer@gmail.com> Signed-off-by: Yury V. Zaytsev <yury@shurup.com>
mc-worker
reviewed
Apr 24, 2026
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| inode->linkname = g_malloc (st->st_size + 1); | ||
| if (st->st_size < 0 || st->st_size >= (off_t) G_MAXSIZE | ||
| || st->st_size > MC_MAXPATHLEN) |
Contributor
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MC_MAXPATHLEN is definitely less than G_MAXSIZE. Thus 2nd test isn't needed.
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Add a bounds check on st_size immediately after it is computed, before it is used in any arithmetic or allocation. A reasonable upper bound for a symlink target is MC_MAXPATHLEN (4096).