From 1826b6d69bbb7f9ae8711827facbb2ad7f8d0aaa Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 20 Sep 2024 12:32:19 +0200 Subject: [PATCH] parport: Proper fix for array out-of-bounds access 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 Link: https://lore.kernel.org/r/20240920103318.19271-1-tiwai@suse.de Signed-off-by: Greg Kroah-Hartman --- drivers/parport/procfs.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/drivers/parport/procfs.c b/drivers/parport/procfs.c index 8400a379186ea..180376c09cb41 100644 --- a/drivers/parport/procfs.c +++ b/drivers/parport/procfs.c @@ -51,12 +51,12 @@ static int do_active_device(struct ctl_table *table, int write, 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 *table, int write, } 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 ctl_table *table, int write, 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; @@ -155,7 +155,7 @@ static int do_hardware_irq(struct ctl_table *table, int write, 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; @@ -182,7 +182,7 @@ static int do_hardware_dma(struct ctl_table *table, int write, 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; @@ -213,7 +213,7 @@ static int do_hardware_modes(struct ctl_table *table, int write, #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); -- 2.47.3