From 02ac3a9ef3a18b58d8f3ea2b6e46de657bf6c4f9 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 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 3ef486cd3d6d..3880460e67f2 100644 --- a/drivers/parport/procfs.c +++ b/drivers/parport/procfs.c @@ -51,12 +51,12 @@ static int do_active_device(const 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(const 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(const 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(const 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(const 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(const 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);