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Get rid of strncpy() calls.

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The poorly named `strncpy` was originally written to
copy data into fixed-sized, disk-resident data structures
in an early version of the research Unix kernel.  Thus, it
has peculiar semantics: it takes source and destination
pointer arguments and a length and will *always* modify
exactly `length` bytes in the destination buffer.  If
the length of the source (which is presumed to be a
NUL-terminated C-stylestring) is `length` or more chars
long, then the result will not be NUL terminated.  If it
is less than `length` bytes long, then the result will be
padded with zeros up to `length`.

This is all well and good for storing a file name into a
fixed-width directory entry in 6th edition Unix, but it's
not useful as a general-purpose string utility.

Replaced with calls to strlcpy(), which always properly
terminates the destination but doesn't have the additional
zeroing behavior.  Since the buffers that we're copying
into were allocated with malloz(), and thus are guaranteed
to be filled with zeros, we're not leaking data, but not
double-zeroing either.

A few other things were changed. Lengths of destination
buffers are now given via `sizeof` instead of manifest
constants.  One call to `memcpy` took the length from the
size of the source argument, thus possibly writing beyond
the end of the destination buffer.  Changed to a call to
strlcpy() with length the sizeof destination.

Signed-off-by: Dan Cross <patchdev@fat-dragon.org>
This commit is contained in:
Dan Cross 2018-10-15 14:37:46 +00:00 committed by Andrew Pamment
parent f01cd5f1a6
commit 931c5625a3
1 changed files with 8 additions and 9 deletions
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17
src/bluewave.c
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@ -89,7 +89,7 @@ int bwave_scan_email(int areano, int totmsgs, FILE *fti_file, FILE *mix_file, FI
memset(&fti, 0, sizeof(FTI_REC)); memset(&fti, 0, sizeof(FTI_REC));
strlcpy(fti.from, sqlite3_column_text(res, 0), sizeof fti.from); strlcpy(fti.from, sqlite3_column_text(res, 0), sizeof fti.from);
strlcpy(fti.to, gUser->loginname, sizeof fti.to); strlcpy(fti.to, gUser->loginname, sizeof fti.to);
strlcpy(fti.subject, sqlite3_column_text(res, 1), fti.subject); strlcpy(fti.subject, sqlite3_column_text(res, 1), sizeof fti.subject);
thetime = sqlite3_column_int(res, 2); thetime = sqlite3_column_int(res, 2);
localtime_r((time_t *)&thetime, &timeStruct); localtime_r((time_t *)&thetime, &timeStruct);
@ -341,18 +341,17 @@ void bwave_create_packet() {
area_count = 0; area_count = 0;
memset(&hdr, 0, sizeof(INF_HEADER)); memset(&hdr, 0, sizeof(INF_HEADER));
hdr.ver = PACKET_LEVEL; hdr.ver = PACKET_LEVEL;
strncpy(hdr.loginname, gUser->loginname, 42); strlcpy(hdr.loginname, gUser->loginname, sizeof hdr.loginname);
//strncpy(hdr.aliasname, gUser->loginname, 42); //strlcpy(hdr.aliasname, gUser->loginname, sizeof hdr.aliasname);
snprintf(hdr.aliasname, sizeof hdr.aliasname, "%s %s", gUser->firstname, gUser->lastname); snprintf(hdr.aliasname, sizeof hdr.aliasname, "%s %s", gUser->firstname, gUser->lastname);
hdr.zone = converts(conf.main_aka->zone); hdr.zone = converts(conf.main_aka->zone);
hdr.node = converts(conf.main_aka->node); hdr.node = converts(conf.main_aka->node);
hdr.net = converts(conf.main_aka->net); hdr.net = converts(conf.main_aka->net);
hdr.point = converts(conf.main_aka->point); hdr.point = converts(conf.main_aka->point);
strncpy(hdr.sysop, conf.sysop_name, 40); strlcpy(hdr.sysop, conf.sysop_name, sizeof hdr.sysop);
strncpy(hdr.systemname, conf.bbs_name, 64); strlcpy(hdr.systemname, conf.bbs_name, sizeof hdr.systemname);
hdr.inf_header_len = converts(sizeof(INF_HEADER)); hdr.inf_header_len = converts(sizeof(INF_HEADER));
hdr.inf_areainfo_len = converts(sizeof(INF_AREA_INFO)); hdr.inf_areainfo_len = converts(sizeof(INF_AREA_INFO));
hdr.mix_structlen = converts(sizeof(MIX_REC)); hdr.mix_structlen = converts(sizeof(MIX_REC));
@ -423,11 +422,11 @@ void bwave_create_packet() {
flags = 0; flags = 0;
area = (INF_AREA_INFO *)malloz(sizeof(INF_AREA_INFO)); area = (INF_AREA_INFO *)malloz(sizeof(INF_AREA_INFO));
snprintf(area->areanum, 6, "%d", area_count + 1); snprintf(area->areanum, sizeof area->areanum, "%d", area_count + 1);
memcpy(area->echotag, conf.mail_conferences[i]->mail_areas[j]->qwkname, strlen(conf.mail_conferences[i]->mail_areas[j]->qwkname)); strlcpy(area->echotag, conf.mail_conferences[i]->mail_areas[j]->qwkname, sizeof area->echotag);
strncpy(area->title, conf.mail_conferences[i]->mail_areas[j]->name, 49); strlcpy(area->title, conf.mail_conferences[i]->mail_areas[j]->name, sizeof area->title);
if (conf.mail_conferences[i]->mail_areas[j]->write_sec_level <= gUser->sec_level) { if (conf.mail_conferences[i]->mail_areas[j]->write_sec_level <= gUser->sec_level) {
flags |= INF_POST; flags |= INF_POST;