| Message ID | 20230610025759.1813-2-demi@invisiblethingslab.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/4] Rip out simple_strtoll() | expand |
[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 <demi@invisiblethingslab.com> > --- > 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" <hch@infradead.org> > [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 <demi@invisiblethingslab.com> >> --- >> 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/20230610/202306102055.ZSJK8Xsj-lkp@intel.com/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/20230610025759.1813-2-demi@invisiblethingslab.com
# 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 <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202306102055.ZSJK8Xsj-lkp@intel.com/
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
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++;
Userspace sets errno to ERANGE, but the kernel can't do that. Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com> --- 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(-)