diff options
Diffstat (limited to 'main/musl/0016-fix-integer-overflow-in-float-printf-needed-precisio.patch')
| -rw-r--r-- | main/musl/0016-fix-integer-overflow-in-float-printf-needed-precisio.patch | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/main/musl/0016-fix-integer-overflow-in-float-printf-needed-precisio.patch b/main/musl/0016-fix-integer-overflow-in-float-printf-needed-precisio.patch new file mode 100644 index 0000000000..fcadc040d2 --- /dev/null +++ b/main/musl/0016-fix-integer-overflow-in-float-printf-needed-precisio.patch @@ -0,0 +1,37 @@ +From 70d2687d85c314963cf280759b23fd4573ff0d82 Mon Sep 17 00:00:00 2001 +From: Rich Felker <dalias@aerifal.cx> +Date: Wed, 19 Oct 2016 20:17:16 -0400 +Subject: [PATCH 16/18] fix integer overflow in float printf needed-precision + computation + +if the requested precision is close to INT_MAX, adding +LDBL_MANT_DIG/3+8 overflows. in practice the resulting undefined +behavior manifests as a large negative result, which is then used to +compute the new end pointer (z) with a wildly out-of-bounds value +(more overflow, more undefined behavior). the end result is at least +incorrect output and character count (return value); worse things do +not seem to happen, but detailed analysis has not been done. + +this patch fixes the overflow by performing the intermediate +computation as unsigned; after division by 9, the final result +necessarily fits in int. +--- + src/stdio/vfprintf.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c +index e439a07..cd17ad7 100644 +--- a/src/stdio/vfprintf.c ++++ b/src/stdio/vfprintf.c +@@ -312,7 +312,7 @@ static int fmt_fp(FILE *f, long double y, int w, int p, int fl, int t) + } + while (e2<0) { + uint32_t carry=0, *b; +- int sh=MIN(9,-e2), need=1+(p+LDBL_MANT_DIG/3+8)/9; ++ int sh=MIN(9,-e2), need=1+(p+LDBL_MANT_DIG/3U+8)/9; + for (d=a; d<z; d++) { + uint32_t rm = *d & (1<<sh)-1; + *d = (*d>>sh) + carry; +-- +2.10.1 + |