| Message ID | 20190317120441.64846-1-liq3ea@163.com |
|---|---|
| State | New |
| Headers | show |
| Series | vnc: fix unalignment access in tight_pack24 | expand |
On Sun, 17 Mar 2019 at 12:09, Li Qiang <liq3ea@163.com> wrote: > > When adding '-fsanitize=undefined' in compiling configuration > and connect VM with vnc, it reports following error: > > ui/vnc-enc-tight.c:910:13: runtime error: load of > misaligned address 0x621000466513 for type 'uint32_t', > which requires 4 byte alignment > > This patch fix this issue. > > Signed-off-by: Li Qiang <liq3ea@163.com> > --- > ui/vnc-enc-tight.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/ui/vnc-enc-tight.c b/ui/vnc-enc-tight.c > index 0b4a5ac71f..7e1be63af3 100644 > --- a/ui/vnc-enc-tight.c > +++ b/ui/vnc-enc-tight.c > @@ -886,11 +886,11 @@ static int tight_compress_data(VncState *vs, int stream_id, size_t bytes, > */ > static void tight_pack24(VncState *vs, uint8_t *buf, size_t count, size_t *ret) > { > - uint32_t *buf32; > + uint8_t *buf8; > uint32_t pix; > int rshift, gshift, bshift; > > - buf32 = (uint32_t *)buf; > + buf8 = buf; > > if (1 /* FIXME */) { > rshift = vs->client_pf.rshift; > @@ -907,10 +907,11 @@ static void tight_pack24(VncState *vs, uint8_t *buf, size_t count, size_t *ret) > } > > while (count--) { > - pix = *buf32++; > + memcpy(&pix, buf8, sizeof(uint32_t)); Better to use ldl_he_p() rather than hand-rolling an unaligned accessor with memcpy(), I think. Is the input data definitely in host endianness order ? > *buf++ = (char)(pix >> rshift); > *buf++ = (char)(pix >> gshift); > *buf++ = (char)(pix >> bshift); > + buf8 += 4; > } > } > > -- > 2.17.1 thanks -- PMM
Peter Maydell <peter.maydell@linaro.org> 于2019年3月17日周日 下午10:10写道： > On Sun, 17 Mar 2019 at 12:09, Li Qiang <liq3ea@163.com> wrote: > > > > When adding '-fsanitize=undefined' in compiling configuration > > and connect VM with vnc, it reports following error: > > > > ui/vnc-enc-tight.c:910:13: runtime error: load of > > misaligned address 0x621000466513 for type 'uint32_t', > > which requires 4 byte alignment > > > > This patch fix this issue. > > > > Signed-off-by: Li Qiang <liq3ea@163.com> > > --- > > ui/vnc-enc-tight.c | 7 ++++--- > > 1 file changed, 4 insertions(+), 3 deletions(-) > > > > diff --git a/ui/vnc-enc-tight.c b/ui/vnc-enc-tight.c > > index 0b4a5ac71f..7e1be63af3 100644 > > --- a/ui/vnc-enc-tight.c > > +++ b/ui/vnc-enc-tight.c > > @@ -886,11 +886,11 @@ static int tight_compress_data(VncState *vs, int > stream_id, size_t bytes, > > */ > > static void tight_pack24(VncState *vs, uint8_t *buf, size_t count, > size_t *ret) > > { > > - uint32_t *buf32; > > + uint8_t *buf8; > > uint32_t pix; > > int rshift, gshift, bshift; > > > > - buf32 = (uint32_t *)buf; > > + buf8 = buf; > > > > if (1 /* FIXME */) { > > rshift = vs->client_pf.rshift; > > @@ -907,10 +907,11 @@ static void tight_pack24(VncState *vs, uint8_t > *buf, size_t count, size_t *ret) > > } > > > > while (count--) { > > - pix = *buf32++; > > + memcpy(&pix, buf8, sizeof(uint32_t)); > > Better to use ldl_he_p() rather than hand-rolling > an unaligned accessor with memcpy(), I think. > > Will do next revision. > Is the input data definitely in host endianness > order ? > AFAICS, Yes. Thanks, Li Qiang > > > *buf++ = (char)(pix >> rshift); > > *buf++ = (char)(pix >> gshift); > > *buf++ = (char)(pix >> bshift); > > + buf8 += 4; > > } > > } > > > > -- > > 2.17.1 > > thanks > -- PMM >
diff --git a/ui/vnc-enc-tight.c b/ui/vnc-enc-tight.c index 0b4a5ac71f..7e1be63af3 100644 --- a/ui/vnc-enc-tight.c +++ b/ui/vnc-enc-tight.c @@ -886,11 +886,11 @@ static int tight_compress_data(VncState *vs, int stream_id, size_t bytes, */ static void tight_pack24(VncState *vs, uint8_t *buf, size_t count, size_t *ret) { - uint32_t *buf32; + uint8_t *buf8; uint32_t pix; int rshift, gshift, bshift; - buf32 = (uint32_t *)buf; + buf8 = buf; if (1 /* FIXME */) { rshift = vs->client_pf.rshift; @@ -907,10 +907,11 @@ static void tight_pack24(VncState *vs, uint8_t *buf, size_t count, size_t *ret) } while (count--) { - pix = *buf32++; + memcpy(&pix, buf8, sizeof(uint32_t)); *buf++ = (char)(pix >> rshift); *buf++ = (char)(pix >> gshift); *buf++ = (char)(pix >> bshift); + buf8 += 4; } }
When adding '-fsanitize=undefined' in compiling configuration and connect VM with vnc, it reports following error: ui/vnc-enc-tight.c:910:13: runtime error: load of misaligned address 0x621000466513 for type 'uint32_t', which requires 4 byte alignment This patch fix this issue. Signed-off-by: Li Qiang <liq3ea@163.com> --- ui/vnc-enc-tight.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)