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Fix TGA RLE read buffer overflow and add EOF error detection (CVE-2021-36489) #38

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Fix TGA RLE read buffer overflow and add EOF error detection (CVE-2021-36489) #38

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ced3b14
Fix TGA RLE read buffer overflow and add EOF error detection
gusnan Nov 26, 2025
594d10d
Add EOF checks after reading color values in RLE routines
gusnan Nov 26, 2025
b7ed6ad
Add EOF checks after raw packet reads in RLE routines
gusnan Nov 26, 2025
f2966c6
Add EOF error detection to PCX RLE decode
gusnan Nov 26, 2025
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17 changes: 14 additions & 3 deletions src/pcx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -124,10 +124,21 @@ BITMAP *load_pcx_pf(PACKFILE *f, RGB *pal)
#endif

while (x < bytes_per_line*bpp/8) {
ch = pack_getc(f);
c = pack_getc(f);
if (c == EOF) {
destroy_bitmap(b);
return NULL;
}
ch = c;
if ((ch & 0xC0) == 0xC0) {
c = (ch & 0x3F);
ch = pack_getc(f);
int run_count = (ch & 0x3F);
c = pack_getc(f);
if (c == EOF) {
destroy_bitmap(b);
return NULL;
}
ch = c;
c = run_count;
}
else
c = 1;
Expand Down
93 changes: 81 additions & 12 deletions src/tga.c
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Original file line number Diff line number Diff line change
Expand Up @@ -39,28 +39,41 @@ static INLINE unsigned char *raw_tga_read8(unsigned char *b, int w, PACKFILE *f)

/* rle_tga_read8:
* Helper for reading 256-color RLE data from TGA files.
* Returns pointer past last written byte, or NULL on error.
*/
static void rle_tga_read8(unsigned char *b, int w, PACKFILE *f)
static unsigned char *rle_tga_read8(unsigned char *b, int w, PACKFILE *f)
{
int value, count, c = 0;

do {
count = pack_getc(f);
if (count == EOF)
return NULL;
if (count & 0x80) {
/* run-length packet */
count = (count & 0x7F) + 1;
if (c + count > w)
count = w - c;
c += count;
value = pack_getc(f);
if (value == EOF)
return NULL;
while (count--)
*b++ = value;
}
else {
/* raw packet */
count++;
if (c + count > w)
count = w - c;
c += count;
b = raw_tga_read8(b, count, f);
if (pack_feof(f))
return NULL;
}
} while (c < w);

return b;
}


Expand Down Expand Up @@ -98,28 +111,41 @@ static unsigned int *raw_tga_read32(unsigned int *b, int w, PACKFILE *f)

/* rle_tga_read32:
* Helper for reading 32-bit RLE data from TGA files.
* Returns pointer past last written element, or NULL on error.
*/
static void rle_tga_read32(unsigned int *b, int w, PACKFILE *f)
static unsigned int *rle_tga_read32(unsigned int *b, int w, PACKFILE *f)
{
int color, count, c = 0;

do {
count = pack_getc(f);
if (count == EOF)
return NULL;
if (count & 0x80) {
/* run-length packet */
count = (count & 0x7F) + 1;
if (c + count > w)
count = w - c;
c += count;
color = single_tga_read32(f);
if (pack_feof(f))
return NULL;
while (count--)
*b++ = color;
}
else {
/* raw packet */
count++;
if (c + count > w)
count = w - c;
c += count;
b = raw_tga_read32(b, count, f);
if (pack_feof(f))
return NULL;
}
} while (c < w);

return b;
}


Expand Down Expand Up @@ -159,18 +185,25 @@ static unsigned char *raw_tga_read24(unsigned char *b, int w, PACKFILE *f)

/* rle_tga_read24:
* Helper for reading 24-bit RLE data from TGA files.
* Returns pointer past last written byte, or NULL on error.
*/
static void rle_tga_read24(unsigned char *b, int w, PACKFILE *f)
static unsigned char *rle_tga_read24(unsigned char *b, int w, PACKFILE *f)
{
int color, count, c = 0;

do {
count = pack_getc(f);
if (count == EOF)
return NULL;
if (count & 0x80) {
/* run-length packet */
count = (count & 0x7F) + 1;
if (c + count > w)
count = w - c;
c += count;
color = single_tga_read24(f);
if (pack_feof(f))
return NULL;
while (count--) {
WRITE3BYTES(b, color);
b += 3;
Expand All @@ -179,10 +212,16 @@ static void rle_tga_read24(unsigned char *b, int w, PACKFILE *f)
else {
/* raw packet */
count++;
if (c + count > w)
count = w - c;
c += count;
b = raw_tga_read24(b, count, f);
if (pack_feof(f))
return NULL;
}
} while (c < w);

return b;
}


Expand All @@ -195,6 +234,7 @@ static INLINE int single_tga_read16(PACKFILE *f)
int value;

value = pack_igetw(f);
value &= 0x7FFF; /* mask out 1-bit alpha value */

return (((value >> 10) & 0x1F) << _rgb_r_shift_15) |
(((value >> 5) & 0x1F) << _rgb_g_shift_15) |
Expand All @@ -218,28 +258,41 @@ static unsigned short *raw_tga_read16(unsigned short *b, int w, PACKFILE *f)

/* rle_tga_read16:
* Helper for reading 16-bit RLE data from TGA files.
* Returns pointer past last written element, or NULL on error.
*/
static void rle_tga_read16(unsigned short *b, int w, PACKFILE *f)
static unsigned short *rle_tga_read16(unsigned short *b, int w, PACKFILE *f)
{
int color, count, c = 0;

do {
count = pack_getc(f);
if (count == EOF)
return NULL;
if (count & 0x80) {
/* run-length packet */
count = (count & 0x7F) + 1;
if (c + count > w)
count = w - c;
c += count;
color = single_tga_read16(f);
if (pack_feof(f))
return NULL;
while (count--)
*b++ = color;
}
else {
/* raw packet */
count++;
if (c + count > w)
count = w - c;
c += count;
b = raw_tga_read16(b, count, f);
if (pack_feof(f))
return NULL;
}
} while (c < w);

return b;
}


Expand Down Expand Up @@ -419,28 +472,44 @@ BITMAP *load_tga_pf(PACKFILE *f, RGB *pal)

case 1:
case 3:
if (compressed)
rle_tga_read8(bmp->line[yc], image_width, f);
if (compressed) {
if (!rle_tga_read8(bmp->line[yc], image_width, f)) {
destroy_bitmap(bmp);
return NULL;
}
}
else
raw_tga_read8(bmp->line[yc], image_width, f);
break;

case 2:
if (bpp == 32) {
if (compressed)
rle_tga_read32((unsigned int *)bmp->line[yc], image_width, f);
if (compressed) {
if (!rle_tga_read32((unsigned int *)bmp->line[yc], image_width, f)) {
destroy_bitmap(bmp);
return NULL;
}
}
else
raw_tga_read32((unsigned int *)bmp->line[yc], image_width, f);
}
else if (bpp == 24) {
if (compressed)
rle_tga_read24(bmp->line[yc], image_width, f);
if (compressed) {
if (!rle_tga_read24(bmp->line[yc], image_width, f)) {
destroy_bitmap(bmp);
return NULL;
}
}
else
raw_tga_read24(bmp->line[yc], image_width, f);
}
else {
if (compressed)
rle_tga_read16((unsigned short *)bmp->line[yc], image_width, f);
if (compressed) {
if (!rle_tga_read16((unsigned short *)bmp->line[yc], image_width, f)) {
destroy_bitmap(bmp);
return NULL;
}
}
else
raw_tga_read16((unsigned short *)bmp->line[yc], image_width, f);
}
Expand Down