diff options
| author | Tom Lane | 2022-12-21 22:51:50 +0000 |
|---|---|---|
| committer | Tom Lane | 2022-12-21 22:51:50 +0000 |
| commit | 701c881f782b93ee29587112390bd3bfe035e78d (patch) | |
| tree | 9c6fa26811eb5060846fcc75bb0bda3141c028ab /contrib/seg/segparse.y | |
| parent | 33dd895ef3316bd1896def6882e9075359d7e9af (diff) | |
Fix contrib/seg to be more wary of long input numbers.
seg stores the number of significant digits in an input number
in a "char" field. If char is signed, and the input is more than
127 digits long, the count can read out as negative causing
seg_out() to print garbage (or, if you're really unlucky,
even crash).
To fix, clamp the digit count to be not more than FLT_DIG.
(In theory this loses some information about what the original
input was, but it doesn't seem like useful information; it would
not survive dump/restore in any case.)
Also, in case there are stored values of the seg type containing
bad data, add a clamp in seg_out's restore() subroutine.
Per bug #17725 from Robins Tharakan. It's been like this
forever, so back-patch to all supported branches.
Discussion: https://postgr.es/m/17725-0a09313b67fbe86e@postgresql.org
Diffstat (limited to 'contrib/seg/segparse.y')
| -rw-r--r-- | contrib/seg/segparse.y | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/contrib/seg/segparse.y b/contrib/seg/segparse.y index 1d2adbbec89..0156c3e0274 100644 --- a/contrib/seg/segparse.y +++ b/contrib/seg/segparse.y @@ -3,6 +3,7 @@ #include "postgres.h" +#include <float.h> #include <math.h> #include "fmgr.h" @@ -20,6 +21,8 @@ static float seg_atof(const char *value); +static int sig_digits(const char *value); + static char strbuf[25] = { '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', @@ -62,9 +65,9 @@ range: boundary PLUMIN deviation result->lower = $1.val - $3.val; result->upper = $1.val + $3.val; sprintf(strbuf, "%g", result->lower); - result->l_sigd = Max(Min(6, significant_digits(strbuf)), Max($1.sigd, $3.sigd)); + result->l_sigd = Max(sig_digits(strbuf), Max($1.sigd, $3.sigd)); sprintf(strbuf, "%g", result->upper); - result->u_sigd = Max(Min(6, significant_digits(strbuf)), Max($1.sigd, $3.sigd)); + result->u_sigd = Max(sig_digits(strbuf), Max($1.sigd, $3.sigd)); result->l_ext = '\0'; result->u_ext = '\0'; } @@ -121,7 +124,7 @@ boundary: SEGFLOAT float val = seg_atof($1); $$.ext = '\0'; - $$.sigd = significant_digits($1); + $$.sigd = sig_digits($1); $$.val = val; } | EXTENSION SEGFLOAT @@ -130,7 +133,7 @@ boundary: SEGFLOAT float val = seg_atof($2); $$.ext = $1[0]; - $$.sigd = significant_digits($2); + $$.sigd = sig_digits($2); $$.val = val; } ; @@ -141,7 +144,7 @@ deviation: SEGFLOAT float val = seg_atof($1); $$.ext = '\0'; - $$.sigd = significant_digits($1); + $$.sigd = sig_digits($1); $$.val = val; } ; @@ -157,3 +160,12 @@ seg_atof(const char *value) datum = DirectFunctionCall1(float4in, CStringGetDatum(value)); return DatumGetFloat4(datum); } + +static int +sig_digits(const char *value) +{ + int n = significant_digits(value); + + /* Clamp, to ensure value will fit in sigd fields */ + return Min(n, FLT_DIG); +} |