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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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b32a09db4f
match_strcpy() is a somewhat creepy function: the caller needs to make sure that the destination buffer is big enough, and when he screws up or forgets, match_strcpy() happily overruns the buffer. There's exactly one customer: v9fs_parse_options(). I believe it currently can't overflow its buffer, but that's not exactly obvious. The source string is a substing of the mount options. The kernel silently truncates those to PAGE_SIZE bytes, including the terminating zero. See compat_sys_mount() and do_mount(). The destination buffer is obtained from __getname(), which allocates from name_cachep, which is initialized by vfs_caches_init() for size PATH_MAX. We're safe as long as PATH_MAX <= PAGE_SIZE. PATH_MAX is 4096. As far as I know, the smallest PAGE_SIZE is also 4096. Here's a patch that makes the code a bit more obviously correct. It doesn't depend on PATH_MAX <= PAGE_SIZE. Signed-off-by: Markus Armbruster <armbru@redhat.com> Cc: Latchesar Ionkov <lucho@ionkov.net> Cc: Jim Meyering <meyering@redhat.com> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
34 lines
917 B
C
34 lines
917 B
C
/*
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* linux/include/linux/parser.h
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*
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* Header for lib/parser.c
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* Intended use of these functions is parsing filesystem argument lists,
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* but could potentially be used anywhere else that simple option=arg
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* parsing is required.
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*/
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/* associates an integer enumerator with a pattern string. */
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struct match_token {
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int token;
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const char *pattern;
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};
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typedef struct match_token match_table_t[];
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/* Maximum number of arguments that match_token will find in a pattern */
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enum {MAX_OPT_ARGS = 3};
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/* Describe the location within a string of a substring */
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typedef struct {
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char *from;
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char *to;
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} substring_t;
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int match_token(char *, match_table_t table, substring_t args[]);
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int match_int(substring_t *, int *result);
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int match_octal(substring_t *, int *result);
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int match_hex(substring_t *, int *result);
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size_t match_strlcpy(char *, const substring_t *, size_t);
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char *match_strdup(const substring_t *);
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