[POWERPC] spufs: Don't leak kernel stack through an empty {i,m}box_info read
Based on an original patch from Arnd Bergmann <arnd.bergmann@de.ibm.com> If there's no entry in the mailbox, then a read on the _info file will return data from an uninitialised variable. This change returns EOF if there's no mailbox info available instead. Signed-off-by: Jeremy Kerr <jk@ozlabs.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
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@ -2026,13 +2026,13 @@ static const struct file_operations spufs_caps_fops = {
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static ssize_t __spufs_mbox_info_read(struct spu_context *ctx,
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char __user *buf, size_t len, loff_t *pos)
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{
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u32 mbox_stat;
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u32 data;
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mbox_stat = ctx->csa.prob.mb_stat_R;
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if (mbox_stat & 0x0000ff) {
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/* EOF if there's no entry in the mbox */
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if (!(ctx->csa.prob.mb_stat_R & 0x0000ff))
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return 0;
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data = ctx->csa.prob.pu_mb_R;
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}
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return simple_read_from_buffer(buf, len, pos, &data, sizeof data);
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}
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@ -2066,13 +2066,13 @@ static const struct file_operations spufs_mbox_info_fops = {
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static ssize_t __spufs_ibox_info_read(struct spu_context *ctx,
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char __user *buf, size_t len, loff_t *pos)
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{
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u32 ibox_stat;
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u32 data;
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ibox_stat = ctx->csa.prob.mb_stat_R;
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if (ibox_stat & 0xff0000) {
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/* EOF if there's no entry in the ibox */
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if (!(ctx->csa.prob.mb_stat_R & 0xff0000))
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return 0;
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data = ctx->csa.priv2.puint_mb_R;
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}
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return simple_read_from_buffer(buf, len, pos, &data, sizeof data);
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}
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