5.4-stable review patch. If anyone has any objections, please let me know.
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From: Samuel Thibault samuel.thibault@ens-lyon.org
[ Upstream commit b6c8dafc9d86eb77e502bb018ec4105e8d2fbf78 ]
When userland echoes 8bit characters to /dev/synth with e.g.
echo -e '\xe9' > /dev/synth
synth_write would get characters beyond 0x7f, and thus negative when char is signed. When given to synth_buffer_add which takes a u16, this would sign-extend and produce a U+ffxy character rather than U+xy. Users thus get garbled text instead of accents in their output.
Let's fix this by making sure that we read unsigned characters.
Signed-off-by: Samuel Thibault samuel.thibault@ens-lyon.org Fixes: 89fc2ae80bb1 ("speakup: extend synth buffer to 16bit unicode characters") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240204155736.2oh4ot7tiaa2wpbh@begin Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/staging/speakup/synth.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/speakup/synth.c b/drivers/staging/speakup/synth.c index 3568bfb89912c..b5944e7bdbf67 100644 --- a/drivers/staging/speakup/synth.c +++ b/drivers/staging/speakup/synth.c @@ -208,8 +208,10 @@ void spk_do_flush(void) wake_up_process(speakup_task); }
-void synth_write(const char *buf, size_t count) +void synth_write(const char *_buf, size_t count) { + const unsigned char *buf = (const unsigned char *) _buf; + while (count--) synth_buffer_add(*buf++); synth_start();