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| author | Quentin Rameau | 2018-04-01 19:49:58 +0200 |
|---|---|---|
| committer | Denys Vlasenko | 2018-04-01 19:51:14 +0200 |
| commit | e2afae6303e871a31a061d03359cfcd5dd86c088 (patch) | |
| tree | 40482184a4ff53ea4fd3439f96e0e7e967a075cc /libbb/get_line_from_file.c | |
| parent | 2da9724b56169f00bd7fb6b9a11c9409a7620981 (diff) | |
| download | busybox-e2afae6303e871a31a061d03359cfcd5dd86c088.zip busybox-e2afae6303e871a31a061d03359cfcd5dd86c088.tar.gz | |
sed: prevent overflow of length from bb_get_chunk_from_file
This fragment did not work right:
temp = bb_get_chunk_from_file(fp, &len);
if (temp) {
/* len > 0 here, it's ok to do temp[len-1] */
char c = temp[len-1];
With "int len" _sign-extending_, temp[len-1] can refer to a wrong location
if len > 0x7fffffff.
Signed-off-by: Quentin Rameau <quinq@fifth.space>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'libbb/get_line_from_file.c')
| -rw-r--r-- | libbb/get_line_from_file.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/libbb/get_line_from_file.c b/libbb/get_line_from_file.c index 941ea12..d100669 100644 --- a/libbb/get_line_from_file.c +++ b/libbb/get_line_from_file.c @@ -10,16 +10,19 @@ */ #include "libbb.h" -char* FAST_FUNC bb_get_chunk_from_file(FILE *file, int *end) +char* FAST_FUNC bb_get_chunk_from_file(FILE *file, size_t *end) { int ch; - unsigned idx = 0; + size_t idx = 0; char *linebuf = NULL; while ((ch = getc(file)) != EOF) { /* grow the line buffer as necessary */ - if (!(idx & 0xff)) + if (!(idx & 0xff)) { + if (idx == ((size_t)-1) - 0xff) + bb_error_msg_and_die(bb_msg_memory_exhausted); linebuf = xrealloc(linebuf, idx + 0x100); + } linebuf[idx++] = (char) ch; if (ch == '\0') break; @@ -49,7 +52,7 @@ char* FAST_FUNC xmalloc_fgets(FILE *file) /* Get line. Remove trailing \n */ char* FAST_FUNC xmalloc_fgetline(FILE *file) { - int i; + size_t i; char *c = bb_get_chunk_from_file(file, &i); if (i && c[--i] == '\n') |