[PATCH] dlls/{mciwave, winmm}: properly handle mmioRead/mmioWrite in case of errors

[Eric Pouech]

In C, an inequality comparison between a signed and an unsigned integer
ends up with an unsigned comparison.
So, force signed comparison to catch both case of errors and partial
read operation.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52628
Signed-off-by: Eric Pouech

---
 dlls/mciwave/mciwave.c |    3 ++-
 dlls/winmm/mmio.c      |    8 +++-----
 dlls/winmm/playsound.c |    3 ++-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/dlls/mciwave/mciwave.c b/dlls/mciwave/mciwave.c
index 1d9abce84a3..3bb271f66ec 100644
--- a/dlls/mciwave/mciwave.c
+++ b/dlls/mciwave/mciwave.c
@@ -291,7 +291,8 @@ static	DWORD WAVE_mciReadFmt(WINE_MCIWAVE* wmw, const MMCKINFO* pckMainRIFF)
     if (!pwfx) return MCIERR_OUT_OF_MEMORY;

r = mmioRead(wmw->hFile, (HPSTR)pwfx, mmckInfo.cksize);
-    if (r < sizeof(PCMWAVEFORMAT)) {
+    /* forcing signed comparison to catch errors (negative value) as well */
+    if (r < (LONG)sizeof(PCMWAVEFORMAT)) {
    HeapFree(GetProcessHeap(), 0, pwfx);
    return MCIERR_INVALID_FILE;
     }
diff --git a/dlls/winmm/mmio.c b/dlls/winmm/mmio.c
index 352da62a215..3bcde1fe34b 100644
--- a/dlls/winmm/mmio.c
+++ b/dlls/winmm/mmio.c
@@ -1231,10 +1231,8 @@ MMRESULT WINAPI mmioDescend(HMMIO hmmio, LPMMCKINFO lpck,

while (TRUE)
     {
-        LONG ix;
-
-        ix = mmioRead(hmmio, (LPSTR)lpck, 3 * sizeof(DWORD));
-        if (ix < 2*sizeof(DWORD))
+        /* forcing signed comparison to catch errors as well */
+        if (mmioRead(hmmio, (LPSTR)lpck, 3 * sizeof(DWORD)) < (LONG)(2*sizeof(DWORD)))
         {
             mmioSeek(hmmio, dwOldPos, SEEK_SET);
             WARN("return ChunkNotFound\n");
@@ -1336,7 +1334,7 @@ MMRESULT WINAPI mmioCreateChunk(HMMIO hmmio, MMCKINFO* lpck, UINT uFlags)

ix = mmioWrite(hmmio, (LPSTR)lpck, size);
     TRACE("after mmioWrite ix = %ld req = %ld, errno = %d\n", ix, size, errno);
-    if (ix < size) {
+    if (ix != size) {
    mmioSeek(hmmio, dwOldPos, SEEK_SET);
    WARN("return CannotWrite\n");
    return MMIOERR_CANNOTWRITE;
diff --git a/dlls/winmm/playsound.c b/dlls/winmm/playsound.c
index 0858f958583..95131bddce6 100644
--- a/dlls/winmm/playsound.c
+++ b/dlls/winmm/playsound.c
@@ -361,7 +361,8 @@ static DWORD WINAPI proc_PlaySound(LPVOID arg)
     lpWaveFormat = HeapAlloc(GetProcessHeap(), 0, mmckInfo.cksize);
     if (!lpWaveFormat)
    goto errCleanUp;
-    if (mmioRead(hmmio, (HPSTR)lpWaveFormat, mmckInfo.cksize) < sizeof(PCMWAVEFORMAT))
+    /* forcing signed comparison to catch errors as well */
+    if (mmioRead(hmmio, (HPSTR)lpWaveFormat, mmckInfo.cksize) < (LONG)sizeof(PCMWAVEFORMAT))
    goto errCleanUp;

TRACE("wFormatTag=%04X !\n", 	lpWaveFormat->wFormatTag);

[Andrew Eikum]

On Mon, Mar 28, 2022 at 02:38:01PM +0200, Eric Pouech wrote:
> In C, an inequality comparison between a signed and an unsigned integer
> ends up with an unsigned comparison.
> So, force signed comparison to catch both case of errors and partial
> read operation.
>
> Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52628
> Signed-off-by: Eric Pouech
>
> dlls/mciwave/mciwave.c |    3 ++-
>  dlls/winmm/mmio.c      |    8 +++-----
>  dlls/winmm/playsound.c |    3 ++-

Let's do one patch per module.
> 3 files changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/dlls/mciwave/mciwave.c b/dlls/mciwave/mciwave.c
> index 1d9abce84a3..3bb271f66ec 100644
> --- a/dlls/mciwave/mciwave.c
> +++ b/dlls/mciwave/mciwave.c
> @@ -291,7 +291,8 @@ static	DWORD WAVE_mciReadFmt(WINE_MCIWAVE* wmw, const MMCKINFO* pckMainRIFF)
>      if (!pwfx) return MCIERR_OUT_OF_MEMORY;
>  r = mmioRead(wmw->hFile, (HPSTR)pwfx, mmckInfo.cksize);
> - if (r < sizeof(PCMWAVEFORMAT)) {
> - /* forcing signed comparison to catch errors (negative value) as well */
> - if (r < (LONG)sizeof(PCMWAVEFORMAT)) {

I don't like the extra comment, but I don't have a much better idea
either.

What do you think about something like this instead?

if (r < 0 || r < sizeof(PCMWAVEFORMAT)) {
        HeapFree(GetProcessHeap(), 0, pwfx);
        return MCIERR_INVALID_FILE;
    }

It's still not great, but I think this makes it more clear how we are
using the API.

Andrew