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| author | Jan Beulich <jbeulich@suse.com> | 2020-03-05 15:04:45 +0100 |
|---|---|---|
| committer | David Gibson <david@gibson.dropbear.id.au> | 2020-03-06 12:58:54 +1100 |
| commit | 73d6e9ecb4179b510408bc526240f829262df361 (patch) | |
| tree | d0e570fb1fcde4957bbbc60def8c3fc61f80de24 | |
| parent | 2525da3dba9beceb96651dc2986581871dbeca30 (diff) | |
| download | dtc-73d6e9ecb4179b510408bc526240f829262df361.tar.gz | |
libfdt: fix undefined behaviour in fdt_splice_()
libfdt: fix undefined behaviour in fdt_splice_()
Along the lines of commit d0b3ab0a0f46 ("libfdt: Fix undefined behaviour
in fdt_offset_ptr()"), fdt_splice_() similarly may not use pointer
arithmetic to do overflow checks. (The left side of the checks added by
d4c7c25c9ed1 ["libfdt: check for potential overrun in _fdt_splice()"]
doesn't really lend itself to similar replacement though.)
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Message-Id: <f2d09e81-7cb8-c5cc-9699-1ac05b0626ff@suse.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
| -rw-r--r-- | libfdt/fdt_rw.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c index 1385425..524b520 100644 --- a/libfdt/fdt_rw.c +++ b/libfdt/fdt_rw.c @@ -46,7 +46,7 @@ static int fdt_rw_probe_(void *fdt) return err_; \ } -static inline int fdt_data_size_(void *fdt) +static inline unsigned int fdt_data_size_(void *fdt) { return fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt); } @@ -54,15 +54,16 @@ static inline int fdt_data_size_(void *fdt) static int fdt_splice_(void *fdt, void *splicepoint, int oldlen, int newlen) { char *p = splicepoint; - char *end = (char *)fdt + fdt_data_size_(fdt); + unsigned int dsize = fdt_data_size_(fdt); + size_t soff = p - (char *)fdt; - if (((p + oldlen) < p) || ((p + oldlen) > end)) + if ((oldlen < 0) || (soff + oldlen < soff) || (soff + oldlen > dsize)) return -FDT_ERR_BADOFFSET; - if ((p < (char *)fdt) || ((end - oldlen + newlen) < (char *)fdt)) + if ((p < (char *)fdt) || (dsize + newlen < oldlen)) return -FDT_ERR_BADOFFSET; - if ((end - oldlen + newlen) > ((char *)fdt + fdt_totalsize(fdt))) + if (dsize - oldlen + newlen > fdt_totalsize(fdt)) return -FDT_ERR_NOSPACE; - memmove(p + newlen, p + oldlen, end - p - oldlen); + memmove(p + newlen, p + oldlen, ((char *)fdt + dsize) - (p + oldlen)); return 0; } |