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authorRay Lai <ray@raylai.com>2016-05-18 14:06:20 +0800
committerGleydson Soares <gsoares@gmail.com>2017-04-08 00:06:42 +0000
commit94b38bdb722052838eb0d940c05995b870db4ea0 (patch)
treecaa3e66b9f3395c55385c5e201ac5ad336b101ef /src/libdraw
parent669713d43f8a014ba481265d4c58c3fe575527b4 (diff)
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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.c4
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;