Userspace sets errno to ERANGE, but the kernel can't do that.
Signed-off-by: Demi Marie Obenour <[email protected]>
---
include/linux/limits.h | 1 +
include/linux/mfd/wl1273-core.h | 3 --
include/vdso/limits.h | 3 ++
lib/vsprintf.c | 80 ++++++++++++++++++++++++---------
4 files changed, 63 insertions(+), 24 deletions(-)
diff --git a/include/linux/limits.h b/include/linux/limits.h
index f6bcc936901071f496e3e85bb6e1d93905b12e32..8f7fd85b41fb46e6992d9e5912da00424119227a 100644
--- a/include/linux/limits.h
+++ b/include/linux/limits.h
@@ -8,6 +8,7 @@
#define SIZE_MAX (~(size_t)0)
#define SSIZE_MAX ((ssize_t)(SIZE_MAX >> 1))
+#define SSIZE_MIN (-SSIZE_MAX - 1)
#define PHYS_ADDR_MAX (~(phys_addr_t)0)
#define U8_MAX ((u8)~0U)
diff --git a/include/linux/mfd/wl1273-core.h b/include/linux/mfd/wl1273-core.h
index c28cf76d5c31ee1c94a9319a2e2d318bf00283a6..b81a229135ed9f756c749122a8341816031c8311 100644
--- a/include/linux/mfd/wl1273-core.h
+++ b/include/linux/mfd/wl1273-core.h
@@ -204,9 +204,6 @@
WL1273_IS2_TRI_OPT | \
WL1273_IS2_RATE_48K)
-#define SCHAR_MIN (-128)
-#define SCHAR_MAX 127
-
#define WL1273_FR_EVENT BIT(0)
#define WL1273_BL_EVENT BIT(1)
#define WL1273_RDS_EVENT BIT(2)
diff --git a/include/vdso/limits.h b/include/vdso/limits.h
index 0197888ad0e00b2f853d3f25ffa764f61cca7385..0cad0a2490e5efc194d874025eb3e3b846a5c7b4 100644
--- a/include/vdso/limits.h
+++ b/include/vdso/limits.h
@@ -2,6 +2,9 @@
#ifndef __VDSO_LIMITS_H
#define __VDSO_LIMITS_H
+#define UCHAR_MAX ((unsigned char)~0U)
+#define SCHAR_MAX ((signed char)(UCHAR_MAX >> 1))
+#define SCHAR_MIN ((signed char)(-SCHAR_MAX - 1))
#define USHRT_MAX ((unsigned short)~0U)
#define SHRT_MAX ((short)(USHRT_MAX >> 1))
#define SHRT_MIN ((short)(-SHRT_MAX - 1))
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index a60d348efb276d66ca07fe464883408df7fdab97..9846d2385f5b9e8f3945a5664d81047e97cf10d5 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -59,7 +59,7 @@
bool no_hash_pointers __ro_after_init;
EXPORT_SYMBOL_GPL(no_hash_pointers);
-static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base)
+static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base, bool *overflow)
{
const char *cp;
unsigned long long result = 0ULL;
@@ -71,6 +71,8 @@ static noinline unsigned long long simple_strntoull(const char *startp, size_t m
if (prefix_chars < max_chars) {
rv = _parse_integer_limit(cp, base, &result, max_chars - prefix_chars);
/* FIXME */
+ if (overflow)
+ *overflow = !!(rv & KSTRTOX_OVERFLOW);
cp += (rv & ~KSTRTOX_OVERFLOW);
} else {
/* Field too short for prefix + digit, skip over without converting */
@@ -94,7 +96,7 @@ static noinline unsigned long long simple_strntoull(const char *startp, size_t m
noinline
unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
{
- return simple_strntoull(cp, INT_MAX, endp, base);
+ return simple_strntoull(cp, INT_MAX, endp, base, NULL);
}
EXPORT_SYMBOL(simple_strtoull);
@@ -130,18 +132,22 @@ long simple_strtol(const char *cp, char **endp, unsigned int base)
EXPORT_SYMBOL(simple_strtol);
static long long simple_strntoll(const char *cp, size_t max_chars, char **endp,
- unsigned int base)
+ unsigned int base, bool *overflow)
{
+ unsigned long long minand;
+ bool negate;
+
/*
* simple_strntoull() safely handles receiving max_chars==0 in the
* case cp[0] == '-' && max_chars == 1.
* If max_chars == 0 we can drop through and pass it to simple_strntoull()
* and the content of *cp is irrelevant.
*/
- if (*cp == '-' && max_chars > 0)
- return -simple_strntoull(cp + 1, max_chars - 1, endp, base);
-
- return simple_strntoull(cp, max_chars, endp, base);
+ negate = *cp == '-' && max_chars > 0;
+ minand = simple_strntoull(cp + negate, max_chars - negate, endp, base, overflow);
+ if (minand > (unsigned long long)LONG_MAX + negate)
+ *overflow = true;
+ return negate ? -minand : minand;
}
static noinline_for_stack
@@ -3427,7 +3433,7 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
unsigned long long u;
} val;
s16 field_width;
- bool is_sign;
+ bool is_sign, overflow;
while (*fmt) {
/* skip any white space in format */
@@ -3635,45 +3641,77 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
if (is_sign)
val.s = simple_strntoll(str,
field_width >= 0 ? field_width : INT_MAX,
- &next, base);
+ &next, base, &overflow);
else
val.u = simple_strntoull(str,
field_width >= 0 ? field_width : INT_MAX,
- &next, base);
+ &next, base, &overflow);
+ if (unlikely(overflow))
+ return -ERANGE;
switch (qualifier) {
case 'H': /* that's 'hh' in format */
- if (is_sign)
+ if (is_sign) {
+ if (unlikely(val.s < SCHAR_MIN || val.s > SCHAR_MAX))
+ return -ERANGE;
*va_arg(args, signed char *) = val.s;
- else
+ } else {
+ if (unlikely(val.u > UCHAR_MAX))
+ return -ERANGE;
*va_arg(args, unsigned char *) = val.u;
+ }
break;
case 'h':
- if (is_sign)
+ if (is_sign) {
+ if (unlikely(val.s < SHRT_MIN || val.s > SHRT_MAX))
+ return -ERANGE;
*va_arg(args, short *) = val.s;
- else
+ } else {
+ if (unlikely(val.u > USHRT_MAX))
+ return -ERANGE;
*va_arg(args, unsigned short *) = val.u;
+ }
break;
case 'l':
- if (is_sign)
+ if (is_sign) {
+ if (unlikely(val.s < LONG_MIN || val.s > LONG_MAX))
+ return -ERANGE;
*va_arg(args, long *) = val.s;
- else
+ } else {
+ if (unlikely(val.u > ULONG_MAX))
+ return -ERANGE;
*va_arg(args, unsigned long *) = val.u;
+ }
break;
case 'L':
- if (is_sign)
+ /* No overflow check needed */
+ if (is_sign) {
*va_arg(args, long long *) = val.s;
- else
+ } else {
*va_arg(args, unsigned long long *) = val.u;
+ }
break;
case 'z':
- *va_arg(args, size_t *) = val.u;
+ if (is_sign) {
+ if (unlikely(val.s < SSIZE_MIN || val.s > SSIZE_MAX))
+ return -ERANGE;
+ *va_arg(args, ssize_t *) = val.s;
+ } else {
+ if (unlikely(val.u > SIZE_MAX))
+ return -ERANGE;
+ *va_arg(args, size_t *) = val.u;
+ }
break;
default:
- if (is_sign)
+ if (is_sign) {
+ if (unlikely(val.s < INT_MIN || val.s > INT_MAX))
+ return -ERANGE;
*va_arg(args, int *) = val.s;
- else
+ } else {
+ if (unlikely(val.u > UINT_MAX))
+ return -ERANGE;
*va_arg(args, unsigned int *) = val.u;
+ }
break;
}
num++;
--
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab
[Adding Richard and Linus as they're having another overflow checking
discussion and we should probably merge those]
On Fri, Jun 09, 2023 at 10:57:57PM -0400, Demi Marie Obenour wrote:
> Userspace sets errno to ERANGE, but the kernel can't do that.
That seems like a very parse commit log, and also kinda besides
the point - the kernel always returns error in-line and not through
errno. I think you need to document here why we want to do the
overflow checking (not that I doubt it, but it really needs to be
in the commit message).
Leaving the rest of the quote here for the new arrivals.
>
> Signed-off-by: Demi Marie Obenour <[email protected]>
> ---
> include/linux/limits.h | 1 +
> include/linux/mfd/wl1273-core.h | 3 --
> include/vdso/limits.h | 3 ++
> lib/vsprintf.c | 80 ++++++++++++++++++++++++---------
> 4 files changed, 63 insertions(+), 24 deletions(-)
>
> diff --git a/include/linux/limits.h b/include/linux/limits.h
> index f6bcc936901071f496e3e85bb6e1d93905b12e32..8f7fd85b41fb46e6992d9e5912da00424119227a 100644
> --- a/include/linux/limits.h
> +++ b/include/linux/limits.h
> @@ -8,6 +8,7 @@
>
> #define SIZE_MAX (~(size_t)0)
> #define SSIZE_MAX ((ssize_t)(SIZE_MAX >> 1))
> +#define SSIZE_MIN (-SSIZE_MAX - 1)
> #define PHYS_ADDR_MAX (~(phys_addr_t)0)
>
> #define U8_MAX ((u8)~0U)
> diff --git a/include/linux/mfd/wl1273-core.h b/include/linux/mfd/wl1273-core.h
> index c28cf76d5c31ee1c94a9319a2e2d318bf00283a6..b81a229135ed9f756c749122a8341816031c8311 100644
> --- a/include/linux/mfd/wl1273-core.h
> +++ b/include/linux/mfd/wl1273-core.h
> @@ -204,9 +204,6 @@
> WL1273_IS2_TRI_OPT | \
> WL1273_IS2_RATE_48K)
>
> -#define SCHAR_MIN (-128)
> -#define SCHAR_MAX 127
> -
> #define WL1273_FR_EVENT BIT(0)
> #define WL1273_BL_EVENT BIT(1)
> #define WL1273_RDS_EVENT BIT(2)
> diff --git a/include/vdso/limits.h b/include/vdso/limits.h
> index 0197888ad0e00b2f853d3f25ffa764f61cca7385..0cad0a2490e5efc194d874025eb3e3b846a5c7b4 100644
> --- a/include/vdso/limits.h
> +++ b/include/vdso/limits.h
> @@ -2,6 +2,9 @@
> #ifndef __VDSO_LIMITS_H
> #define __VDSO_LIMITS_H
>
> +#define UCHAR_MAX ((unsigned char)~0U)
> +#define SCHAR_MAX ((signed char)(UCHAR_MAX >> 1))
> +#define SCHAR_MIN ((signed char)(-SCHAR_MAX - 1))
> #define USHRT_MAX ((unsigned short)~0U)
> #define SHRT_MAX ((short)(USHRT_MAX >> 1))
> #define SHRT_MIN ((short)(-SHRT_MAX - 1))
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index a60d348efb276d66ca07fe464883408df7fdab97..9846d2385f5b9e8f3945a5664d81047e97cf10d5 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -59,7 +59,7 @@
> bool no_hash_pointers __ro_after_init;
> EXPORT_SYMBOL_GPL(no_hash_pointers);
>
> -static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base)
> +static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base, bool *overflow)
> {
> const char *cp;
> unsigned long long result = 0ULL;
> @@ -71,6 +71,8 @@ static noinline unsigned long long simple_strntoull(const char *startp, size_t m
> if (prefix_chars < max_chars) {
> rv = _parse_integer_limit(cp, base, &result, max_chars - prefix_chars);
> /* FIXME */
> + if (overflow)
> + *overflow = !!(rv & KSTRTOX_OVERFLOW);
> cp += (rv & ~KSTRTOX_OVERFLOW);
> } else {
> /* Field too short for prefix + digit, skip over without converting */
> @@ -94,7 +96,7 @@ static noinline unsigned long long simple_strntoull(const char *startp, size_t m
> noinline
> unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int base)
> {
> - return simple_strntoull(cp, INT_MAX, endp, base);
> + return simple_strntoull(cp, INT_MAX, endp, base, NULL);
> }
> EXPORT_SYMBOL(simple_strtoull);
>
> @@ -130,18 +132,22 @@ long simple_strtol(const char *cp, char **endp, unsigned int base)
> EXPORT_SYMBOL(simple_strtol);
>
> static long long simple_strntoll(const char *cp, size_t max_chars, char **endp,
> - unsigned int base)
> + unsigned int base, bool *overflow)
> {
> + unsigned long long minand;
> + bool negate;
> +
> /*
> * simple_strntoull() safely handles receiving max_chars==0 in the
> * case cp[0] == '-' && max_chars == 1.
> * If max_chars == 0 we can drop through and pass it to simple_strntoull()
> * and the content of *cp is irrelevant.
> */
> - if (*cp == '-' && max_chars > 0)
> - return -simple_strntoull(cp + 1, max_chars - 1, endp, base);
> -
> - return simple_strntoull(cp, max_chars, endp, base);
> + negate = *cp == '-' && max_chars > 0;
> + minand = simple_strntoull(cp + negate, max_chars - negate, endp, base, overflow);
> + if (minand > (unsigned long long)LONG_MAX + negate)
> + *overflow = true;
> + return negate ? -minand : minand;
> }
>
> static noinline_for_stack
> @@ -3427,7 +3433,7 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
> unsigned long long u;
> } val;
> s16 field_width;
> - bool is_sign;
> + bool is_sign, overflow;
>
> while (*fmt) {
> /* skip any white space in format */
> @@ -3635,45 +3641,77 @@ int vsscanf(const char *buf, const char *fmt, va_list args)
> if (is_sign)
> val.s = simple_strntoll(str,
> field_width >= 0 ? field_width : INT_MAX,
> - &next, base);
> + &next, base, &overflow);
> else
> val.u = simple_strntoull(str,
> field_width >= 0 ? field_width : INT_MAX,
> - &next, base);
> + &next, base, &overflow);
> + if (unlikely(overflow))
> + return -ERANGE;
>
> switch (qualifier) {
> case 'H': /* that's 'hh' in format */
> - if (is_sign)
> + if (is_sign) {
> + if (unlikely(val.s < SCHAR_MIN || val.s > SCHAR_MAX))
> + return -ERANGE;
> *va_arg(args, signed char *) = val.s;
> - else
> + } else {
> + if (unlikely(val.u > UCHAR_MAX))
> + return -ERANGE;
> *va_arg(args, unsigned char *) = val.u;
> + }
> break;
> case 'h':
> - if (is_sign)
> + if (is_sign) {
> + if (unlikely(val.s < SHRT_MIN || val.s > SHRT_MAX))
> + return -ERANGE;
> *va_arg(args, short *) = val.s;
> - else
> + } else {
> + if (unlikely(val.u > USHRT_MAX))
> + return -ERANGE;
> *va_arg(args, unsigned short *) = val.u;
> + }
> break;
> case 'l':
> - if (is_sign)
> + if (is_sign) {
> + if (unlikely(val.s < LONG_MIN || val.s > LONG_MAX))
> + return -ERANGE;
> *va_arg(args, long *) = val.s;
> - else
> + } else {
> + if (unlikely(val.u > ULONG_MAX))
> + return -ERANGE;
> *va_arg(args, unsigned long *) = val.u;
> + }
> break;
> case 'L':
> - if (is_sign)
> + /* No overflow check needed */
> + if (is_sign) {
> *va_arg(args, long long *) = val.s;
> - else
> + } else {
> *va_arg(args, unsigned long long *) = val.u;
> + }
> break;
> case 'z':
> - *va_arg(args, size_t *) = val.u;
> + if (is_sign) {
> + if (unlikely(val.s < SSIZE_MIN || val.s > SSIZE_MAX))
> + return -ERANGE;
> + *va_arg(args, ssize_t *) = val.s;
> + } else {
> + if (unlikely(val.u > SIZE_MAX))
> + return -ERANGE;
> + *va_arg(args, size_t *) = val.u;
> + }
> break;
> default:
> - if (is_sign)
> + if (is_sign) {
> + if (unlikely(val.s < INT_MIN || val.s > INT_MAX))
> + return -ERANGE;
> *va_arg(args, int *) = val.s;
> - else
> + } else {
> + if (unlikely(val.u > UINT_MAX))
> + return -ERANGE;
> *va_arg(args, unsigned int *) = val.u;
> + }
> break;
> }
> num++;
> --
> Sincerely,
> Demi Marie Obenour (she/her/hers)
> Invisible Things Lab
>
---end quoted text---
----- Ursprüngliche Mail -----
> Von: "Christoph Hellwig" <[email protected]>
> [Adding Richard and Linus as they're having another overflow checking
> discussion and we should probably merge those]
Thx for letting me know!
> On Fri, Jun 09, 2023 at 10:57:57PM -0400, Demi Marie Obenour wrote:
>> Userspace sets errno to ERANGE, but the kernel can't do that.
>
> That seems like a very parse commit log, and also kinda besides
> the point - the kernel always returns error in-line and not through
> errno. I think you need to document here why we want to do the
> overflow checking (not that I doubt it, but it really needs to be
> in the commit message).
>
> Leaving the rest of the quote here for the new arrivals.
>
>>
>> Signed-off-by: Demi Marie Obenour <[email protected]>
>> ---
>> include/linux/limits.h | 1 +
>> include/linux/mfd/wl1273-core.h | 3 --
>> include/vdso/limits.h | 3 ++
>> lib/vsprintf.c | 80 ++++++++++++++++++++++++---------
>> 4 files changed, 63 insertions(+), 24 deletions(-)
>>
>> diff --git a/include/linux/limits.h b/include/linux/limits.h
>> index
>> f6bcc936901071f496e3e85bb6e1d93905b12e32..8f7fd85b41fb46e6992d9e5912da00424119227a
>> 100644
>> --- a/include/linux/limits.h
>> +++ b/include/linux/limits.h
>> @@ -8,6 +8,7 @@
>>
>> #define SIZE_MAX (~(size_t)0)
>> #define SSIZE_MAX ((ssize_t)(SIZE_MAX >> 1))
>> +#define SSIZE_MIN (-SSIZE_MAX - 1)
>> #define PHYS_ADDR_MAX (~(phys_addr_t)0)
>>
>> #define U8_MAX ((u8)~0U)
>> diff --git a/include/linux/mfd/wl1273-core.h b/include/linux/mfd/wl1273-core.h
>> index
>> c28cf76d5c31ee1c94a9319a2e2d318bf00283a6..b81a229135ed9f756c749122a8341816031c8311
>> 100644
>> --- a/include/linux/mfd/wl1273-core.h
>> +++ b/include/linux/mfd/wl1273-core.h
>> @@ -204,9 +204,6 @@
>> WL1273_IS2_TRI_OPT | \
>> WL1273_IS2_RATE_48K)
>>
>> -#define SCHAR_MIN (-128)
>> -#define SCHAR_MAX 127
>> -
>> #define WL1273_FR_EVENT BIT(0)
>> #define WL1273_BL_EVENT BIT(1)
>> #define WL1273_RDS_EVENT BIT(2)
>> diff --git a/include/vdso/limits.h b/include/vdso/limits.h
>> index
>> 0197888ad0e00b2f853d3f25ffa764f61cca7385..0cad0a2490e5efc194d874025eb3e3b846a5c7b4
>> 100644
>> --- a/include/vdso/limits.h
>> +++ b/include/vdso/limits.h
>> @@ -2,6 +2,9 @@
>> #ifndef __VDSO_LIMITS_H
>> #define __VDSO_LIMITS_H
>>
>> +#define UCHAR_MAX ((unsigned char)~0U)
>> +#define SCHAR_MAX ((signed char)(UCHAR_MAX >> 1))
>> +#define SCHAR_MIN ((signed char)(-SCHAR_MAX - 1))
>> #define USHRT_MAX ((unsigned short)~0U)
>> #define SHRT_MAX ((short)(USHRT_MAX >> 1))
>> #define SHRT_MIN ((short)(-SHRT_MAX - 1))
>> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
>> index
>> a60d348efb276d66ca07fe464883408df7fdab97..9846d2385f5b9e8f3945a5664d81047e97cf10d5
>> 100644
>> --- a/lib/vsprintf.c
>> +++ b/lib/vsprintf.c
>> @@ -59,7 +59,7 @@
>> bool no_hash_pointers __ro_after_init;
>> EXPORT_SYMBOL_GPL(no_hash_pointers);
>>
>> -static noinline unsigned long long simple_strntoull(const char *startp, size_t
>> max_chars, char **endp, unsigned int base)
>> +static noinline unsigned long long simple_strntoull(const char *startp, size_t
>> max_chars, char **endp, unsigned int base, bool *overflow)
>> {
>> const char *cp;
>> unsigned long long result = 0ULL;
>> @@ -71,6 +71,8 @@ static noinline unsigned long long simple_strntoull(const char
>> *startp, size_t m
>> if (prefix_chars < max_chars) {
>> rv = _parse_integer_limit(cp, base, &result, max_chars - prefix_chars);
>> /* FIXME */
>> + if (overflow)
>> + *overflow = !!(rv & KSTRTOX_OVERFLOW);
>> cp += (rv & ~KSTRTOX_OVERFLOW);
>> } else {
>> /* Field too short for prefix + digit, skip over without converting */
>> @@ -94,7 +96,7 @@ static noinline unsigned long long simple_strntoull(const char
>> *startp, size_t m
>> noinline
>> unsigned long long simple_strtoull(const char *cp, char **endp, unsigned int
>> base)
>> {
>> - return simple_strntoull(cp, INT_MAX, endp, base);
>> + return simple_strntoull(cp, INT_MAX, endp, base, NULL);
>> }
>> EXPORT_SYMBOL(simple_strtoull);
>>
>> @@ -130,18 +132,22 @@ long simple_strtol(const char *cp, char **endp, unsigned
>> int base)
>> EXPORT_SYMBOL(simple_strtol);
>>
>> static long long simple_strntoll(const char *cp, size_t max_chars, char **endp,
>> - unsigned int base)
>> + unsigned int base, bool *overflow)
>> {
>> + unsigned long long minand;
>> + bool negate;
>> +
>> /*
>> * simple_strntoull() safely handles receiving max_chars==0 in the
>> * case cp[0] == '-' && max_chars == 1.
>> * If max_chars == 0 we can drop through and pass it to simple_strntoull()
>> * and the content of *cp is irrelevant.
>> */
>> - if (*cp == '-' && max_chars > 0)
>> - return -simple_strntoull(cp + 1, max_chars - 1, endp, base);
>> -
>> - return simple_strntoull(cp, max_chars, endp, base);
>> + negate = *cp == '-' && max_chars > 0;
>> + minand = simple_strntoull(cp + negate, max_chars - negate, endp, base,
>> overflow);
>> + if (minand > (unsigned long long)LONG_MAX + negate)
>> + *overflow = true;
>> + return negate ? -minand : minand;
>> }
>>
>> static noinline_for_stack
>> @@ -3427,7 +3433,7 @@ int vsscanf(const char *buf, const char *fmt, va_list
>> args)
>> unsigned long long u;
>> } val;
>> s16 field_width;
>> - bool is_sign;
>> + bool is_sign, overflow;
>>
>> while (*fmt) {
>> /* skip any white space in format */
>> @@ -3635,45 +3641,77 @@ int vsscanf(const char *buf, const char *fmt, va_list
>> args)
>> if (is_sign)
>> val.s = simple_strntoll(str,
>> field_width >= 0 ? field_width : INT_MAX,
>> - &next, base);
>> + &next, base, &overflow);
>> else
>> val.u = simple_strntoull(str,
>> field_width >= 0 ? field_width : INT_MAX,
>> - &next, base);
>> + &next, base, &overflow);
>> + if (unlikely(overflow))
>> + return -ERANGE;
>>
>> switch (qualifier) {
>> case 'H': /* that's 'hh' in format */
>> - if (is_sign)
>> + if (is_sign) {
>> + if (unlikely(val.s < SCHAR_MIN || val.s > SCHAR_MAX))
>> + return -ERANGE;
>> *va_arg(args, signed char *) = val.s;
>> - else
>> + } else {
>> + if (unlikely(val.u > UCHAR_MAX))
>> + return -ERANGE;
>> *va_arg(args, unsigned char *) = val.u;
>> + }
>> break;
>> case 'h':
>> - if (is_sign)
>> + if (is_sign) {
>> + if (unlikely(val.s < SHRT_MIN || val.s > SHRT_MAX))
>> + return -ERANGE;
Returning a negative value here will break many existing in-kernel users.
Most users just check for the number of matched elements.
Linus' idea was returning 0 upon overflow (nothing matched) and allowing
overflows (if really needed) by adding a new format string qualifier "!".
e.g. "%!d".
Thanks,
//richard
Hi Demi,
kernel test robot noticed the following build warnings:
[auto build test WARNING on lee-mfd/for-mfd-next]
[also build test WARNING on lee-leds/for-leds-next linus/master v6.4-rc5 next-20230609]
[cannot apply to xen-tip/linux-next lee-mfd/for-mfd-fixes]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Demi-Marie-Obenour/vsscanf-Return-ERANGE-on-integer-overflow/20230610-110026
base: https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git for-mfd-next
patch link: https://lore.kernel.org/r/20230610025759.1813-2-demi%40invisiblethingslab.com
patch subject: [PATCH 2/4] vsscanf(): Return -ERANGE on integer overflow
config: i386-allyesconfig (https://download.01.org/0day-ci/archive/20230610/[email protected]/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build):
git remote add lee-mfd https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git
git fetch lee-mfd for-mfd-next
git checkout lee-mfd/for-mfd-next
b4 shazam https://lore.kernel.org/r/[email protected]
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=i386 olddefconfig
make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/staging/media/atomisp/
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
All warnings (new ones prefixed by >>):
In file included from drivers/staging/media/atomisp//pci/ia_css_acc_types.h:25,
from drivers/staging/media/atomisp//pci/ia_css_pipe_public.h:29,
from drivers/staging/media/atomisp//pci/ia_css_stream_public.h:25,
from drivers/staging/media/atomisp//pci/runtime/binary/interface/ia_css_binary.h:23,
from drivers/staging/media/atomisp//pci/runtime/debug/interface/ia_css_debug.h:25,
from drivers/staging/media/atomisp/pci/isp/kernels/macc/macc_1.0/ia_css_macc.host.c:18:
>> drivers/staging/media/atomisp//pci/hive_isp_css_include/platform_support.h:30: warning: "UCHAR_MAX" redefined
30 | #define UCHAR_MAX (255)
|
In file included from include/linux/limits.h:7,
from drivers/staging/media/atomisp//pci/hive_isp_css_include/type_support.h:37,
from drivers/staging/media/atomisp//pci/ia_css_types.h:27,
from drivers/staging/media/atomisp/pci/isp/kernels/macc/macc_1.0/ia_css_macc.host.c:16:
include/vdso/limits.h:5: note: this is the location of the previous definition
5 | #define UCHAR_MAX ((unsigned char)~0U)
|
vim +/UCHAR_MAX +30 drivers/staging/media/atomisp//pci/hive_isp_css_include/platform_support.h
ad85094b293e40 drivers/staging/media/atomisp/pci/atomisp2/css2400/hive_isp_css_include/platform_support.h Mauro Carvalho Chehab 2020-04-19 27
ad85094b293e40 drivers/staging/media/atomisp/pci/atomisp2/css2400/hive_isp_css_include/platform_support.h Mauro Carvalho Chehab 2020-04-19 28 #define UINT16_MAX USHRT_MAX
ad85094b293e40 drivers/staging/media/atomisp/pci/atomisp2/css2400/hive_isp_css_include/platform_support.h Mauro Carvalho Chehab 2020-04-19 29 #define UINT32_MAX UINT_MAX
ad85094b293e40 drivers/staging/media/atomisp/pci/atomisp2/css2400/hive_isp_css_include/platform_support.h Mauro Carvalho Chehab 2020-04-19 @30 #define UCHAR_MAX (255)
ad85094b293e40 drivers/staging/media/atomisp/pci/atomisp2/css2400/hive_isp_css_include/platform_support.h Mauro Carvalho Chehab 2020-04-19 31
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