4.19-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
commit 02ac3a9ef3a18b58d8f3ea2b6e46de657bf6c4f9 upstream.
The recent fix for array out-of-bounds accesses replaced sprintf() calls blindly with snprintf(). However, since snprintf() returns the would-be-printed size, not the actually output size, the length calculation can still go over the given limit.
Use scnprintf() instead of snprintf(), which returns the actually output letters, for addressing the potential out-of-bounds access properly.
Fixes: ab11dac93d2d ("dev/parport: fix the array out-of-bounds risk") Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai tiwai@suse.de Link: https://lore.kernel.org/r/20240920103318.19271-1-tiwai@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/parport/procfs.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-)
--- a/drivers/parport/procfs.c +++ b/drivers/parport/procfs.c @@ -51,12 +51,12 @@ static int do_active_device(struct ctl_t for (dev = port->devices; dev ; dev = dev->next) { if(dev == port->cad) { - len += snprintf(buffer, sizeof(buffer), "%s\n", dev->name); + len += scnprintf(buffer, sizeof(buffer), "%s\n", dev->name); } }
if(!len) { - len += snprintf(buffer, sizeof(buffer), "%s\n", "none"); + len += scnprintf(buffer, sizeof(buffer), "%s\n", "none"); }
if (len > *lenp) @@ -87,19 +87,19 @@ static int do_autoprobe(struct ctl_table } if ((str = info->class_name) != NULL) - len += snprintf (buffer + len, sizeof(buffer) - len, "CLASS:%s;\n", str); + len += scnprintf (buffer + len, sizeof(buffer) - len, "CLASS:%s;\n", str);
if ((str = info->model) != NULL) - len += snprintf (buffer + len, sizeof(buffer) - len, "MODEL:%s;\n", str); + len += scnprintf (buffer + len, sizeof(buffer) - len, "MODEL:%s;\n", str);
if ((str = info->mfr) != NULL) - len += snprintf (buffer + len, sizeof(buffer) - len, "MANUFACTURER:%s;\n", str); + len += scnprintf (buffer + len, sizeof(buffer) - len, "MANUFACTURER:%s;\n", str);
if ((str = info->description) != NULL) - len += snprintf (buffer + len, sizeof(buffer) - len, "DESCRIPTION:%s;\n", str); + len += scnprintf (buffer + len, sizeof(buffer) - len, "DESCRIPTION:%s;\n", str);
if ((str = info->cmdset) != NULL) - len += snprintf (buffer + len, sizeof(buffer) - len, "COMMAND SET:%s;\n", str); + len += scnprintf (buffer + len, sizeof(buffer) - len, "COMMAND SET:%s;\n", str);
if (len > *lenp) len = *lenp; @@ -128,7 +128,7 @@ static int do_hardware_base_addr(struct if (write) /* permissions prevent this anyway */ return -EACCES;
- len += snprintf (buffer, sizeof(buffer), "%lu\t%lu\n", port->base, port->base_hi); + len += scnprintf (buffer, sizeof(buffer), "%lu\t%lu\n", port->base, port->base_hi);
if (len > *lenp) len = *lenp; @@ -156,7 +156,7 @@ static int do_hardware_irq(struct ctl_ta if (write) /* permissions prevent this anyway */ return -EACCES;
- len += snprintf (buffer, sizeof(buffer), "%d\n", port->irq); + len += scnprintf (buffer, sizeof(buffer), "%d\n", port->irq);
if (len > *lenp) len = *lenp; @@ -184,7 +184,7 @@ static int do_hardware_dma(struct ctl_ta if (write) /* permissions prevent this anyway */ return -EACCES;
- len += snprintf (buffer, sizeof(buffer), "%d\n", port->dma); + len += scnprintf (buffer, sizeof(buffer), "%d\n", port->dma);
if (len > *lenp) len = *lenp; @@ -216,7 +216,7 @@ static int do_hardware_modes(struct ctl_ #define printmode(x) \ do { \ if (port->modes & PARPORT_MODE_##x) \ - len += snprintf(buffer + len, sizeof(buffer) - len, "%s%s", f++ ? "," : "", #x); \ + len += scnprintf(buffer + len, sizeof(buffer) - len, "%s%s", f++ ? "," : "", #x); \ } while (0) int f = 0; printmode(PCSPP);