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| author | Ray Lai <ray@raylai.com> | 2016-05-18 14:06:20 +0800 |
|---|---|---|
| committer | Gleydson Soares <gsoares@gmail.com> | 2017-04-08 00:06:42 +0000 |
| commit | 94b38bdb722052838eb0d940c05995b870db4ea0 (patch) | |
| tree | caa3e66b9f3395c55385c5e201ac5ad336b101ef /src/libdraw | |
| parent | 669713d43f8a014ba481265d4c58c3fe575527b4 (diff) | |
| download | plan9port-94b38bdb722052838eb0d940c05995b870db4ea0.tar.gz plan9port-94b38bdb722052838eb0d940c05995b870db4ea0.tar.bz2 plan9port-94b38bdb722052838eb0d940c05995b870db4ea0.zip | |
libdraw: replace hand-rolled realloc, preventing buffer overflow.
The original buffer is f->nsubf*sizeof *subf bytes (oldsize) large.
Once it's full, a new buffer of (f->nsubf+DSUBF)*sizeof *subf
(newsize) is mallocated. Unfortunately memmove() reads (newsize)
bytes from the original (oldsize) buffer, causing a buffer overflow.
By switching to realloc(), we don't need to do buffer size calculation,
memmoving, and freeing of the original buffer.
Change-Id: Ibf85bc06abe1c8275b11acb1d7d346a14291d2cd
Reviewed-on: https://plan9port-review.googlesource.com/1520
Reviewed-by: Gleydson Soares <gsoares@gmail.com>
Diffstat (limited to 'src/libdraw')
| -rw-r--r-- | src/libdraw/font.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/src/libdraw/font.c b/src/libdraw/font.c index 8370606e..13bcd267 100644 --- a/src/libdraw/font.c +++ b/src/libdraw/font.c @@ -222,16 +222,14 @@ loadchar(Font *f, Rune r, Cacheinfo *c, int h, int noflush, char **subfontname) subf->age = 0; }else{ /* too recent; grow instead */ of = f->subf; - f->subf = malloc((f->nsubf+DSUBF)*sizeof *subf); + f->subf = realloc(of, (f->nsubf+DSUBF)*sizeof *subf); if(f->subf == nil){ f->subf = of; goto Toss; } - memmove(f->subf, of, (f->nsubf+DSUBF)*sizeof *subf); memset(f->subf+f->nsubf, 0, DSUBF*sizeof *subf); subf = &f->subf[f->nsubf]; f->nsubf += DSUBF; - free(of); } } subf->age = 0; |