Fix off-by-one errors and potential buffer overruns
WRT handling file and link names that reach the allowed maximum for old tar and ustar archive formats. PR: bin/40466 Submitted by: Cyrille Lefevre <email in the PR> (portions) Reviewed by: freebsd-arch (silence) MFC after: 1 month
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53d0031d37
commit
5512dc5460
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=137645
@ -387,7 +387,13 @@ tar_rd(ARCHD *arcn, char *buf)
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* copy out the name and values in the stat buffer
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*/
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hd = (HD_TAR *)buf;
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arcn->nlen = l_strncpy(arcn->name, hd->name, sizeof(arcn->name) - 1);
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/*
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* old tar format specifies the name always be null-terminated,
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* but let's be robust to broken archives.
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* the same applies to handling links below.
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*/
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arcn->nlen = l_strncpy(arcn->name, hd->name,
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MIN(sizeof(hd->name), sizeof(arcn->name)) - 1);
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arcn->name[arcn->nlen] = '\0';
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arcn->sb.st_mode = (mode_t)(asc_ul(hd->mode,sizeof(hd->mode),OCT) &
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0xfff);
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@ -417,7 +423,7 @@ tar_rd(ARCHD *arcn, char *buf)
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*/
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arcn->type = PAX_SLK;
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arcn->ln_nlen = l_strncpy(arcn->ln_name, hd->linkname,
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sizeof(arcn->ln_name) - 1);
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MIN(sizeof(hd->linkname), sizeof(arcn->ln_name)) - 1);
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arcn->ln_name[arcn->ln_nlen] = '\0';
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arcn->sb.st_mode |= S_IFLNK;
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break;
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@ -429,7 +435,7 @@ tar_rd(ARCHD *arcn, char *buf)
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arcn->type = PAX_HLK;
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arcn->sb.st_nlink = 2;
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arcn->ln_nlen = l_strncpy(arcn->ln_name, hd->linkname,
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sizeof(arcn->ln_name) - 1);
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MIN(sizeof(hd->linkname), sizeof(arcn->ln_name)) - 1);
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arcn->ln_name[arcn->ln_nlen] = '\0';
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/*
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@ -533,7 +539,7 @@ tar_wr(ARCHD *arcn)
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case PAX_SLK:
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case PAX_HLK:
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case PAX_HRG:
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if (arcn->ln_nlen > (int)sizeof(hd->linkname)) {
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if (arcn->ln_nlen >= (int)sizeof(hd->linkname)) {
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paxwarn(1,"Link name too long for tar %s", arcn->ln_name);
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return(1);
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}
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@ -749,12 +755,19 @@ ustar_rd(ARCHD *arcn, char *buf)
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*/
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dest = arcn->name;
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if (*(hd->prefix) != '\0') {
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cnt = l_strncpy(dest, hd->prefix, sizeof(arcn->name) - 2);
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cnt = l_strncpy(dest, hd->prefix,
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MIN(sizeof(hd->prefix), sizeof(arcn->name) - 2));
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dest += cnt;
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*dest++ = '/';
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cnt++;
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}
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arcn->nlen = cnt + l_strncpy(dest, hd->name, sizeof(arcn->name) - cnt);
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/*
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* ustar format specifies the name may be unterminated
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* if it fills the entire field. this also applies to
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* the prefix and the linkname.
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*/
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arcn->nlen = cnt + l_strncpy(dest, hd->name,
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MIN(sizeof(hd->name), sizeof(arcn->name) - cnt - 1));
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arcn->name[arcn->nlen] = '\0';
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/*
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@ -848,7 +861,7 @@ ustar_rd(ARCHD *arcn, char *buf)
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* copy the link name
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*/
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arcn->ln_nlen = l_strncpy(arcn->ln_name, hd->linkname,
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sizeof(arcn->ln_name) - 1);
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MIN(sizeof(hd->linkname), sizeof(arcn->ln_name) - 1));
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arcn->ln_name[arcn->ln_nlen] = '\0';
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break;
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case CONTTYPE:
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@ -900,7 +913,7 @@ ustar_wr(ARCHD *arcn)
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*/
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if (((arcn->type == PAX_SLK) || (arcn->type == PAX_HLK) ||
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(arcn->type == PAX_HRG)) &&
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(arcn->ln_nlen >= (int)sizeof(hd->linkname))) {
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(arcn->ln_nlen > (int)sizeof(hd->linkname))) {
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paxwarn(1, "Link name too long for ustar %s", arcn->ln_name);
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return(1);
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}
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@ -925,17 +938,16 @@ ustar_wr(ARCHD *arcn)
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* occur, we remove the / and copy the first part to the prefix
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*/
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*pt = '\0';
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l_strncpy(hd->prefix, arcn->name, sizeof(hd->prefix) - 1);
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l_strncpy(hd->prefix, arcn->name, sizeof(hd->prefix));
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*pt++ = '/';
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} else
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memset(hd->prefix, 0, sizeof(hd->prefix));
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/*
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* copy the name part. this may be the whole path or the part after
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* the prefix
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* the prefix. both the name and prefix may fill the entire field.
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*/
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l_strncpy(hd->name, pt, sizeof(hd->name) - 1);
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hd->name[sizeof(hd->name) - 1] = '\0';
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l_strncpy(hd->name, pt, sizeof(hd->name));
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/*
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* set the fields in the header that are type dependent
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@ -978,8 +990,8 @@ ustar_wr(ARCHD *arcn)
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hd->typeflag = SYMTYPE;
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else
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hd->typeflag = LNKTYPE;
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l_strncpy(hd->linkname,arcn->ln_name, sizeof(hd->linkname) - 1);
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hd->linkname[sizeof(hd->linkname) - 1] = '\0';
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/* the link name may occupy the entire field in ustar */
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l_strncpy(hd->linkname,arcn->ln_name, sizeof(hd->linkname));
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memset(hd->devmajor, 0, sizeof(hd->devmajor));
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memset(hd->devminor, 0, sizeof(hd->devminor));
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if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 3))
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@ -1072,9 +1084,9 @@ name_split(char *name, int len)
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* check to see if the file name is small enough to fit in the name
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* field. if so just return a pointer to the name.
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*/
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if (len < TNMSZ)
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if (len <= TNMSZ)
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return(name);
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if (len > (TPFSZ + TNMSZ))
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if (len > (TPFSZ + TNMSZ + 1))
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return(NULL);
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/*
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@ -1083,7 +1095,7 @@ name_split(char *name, int len)
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* to find the biggest piece to fit in the name field (or the smallest
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* prefix we can find)
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*/
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start = name + len - TNMSZ;
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start = name + len - TNMSZ - 1;
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while ((*start != '\0') && (*start != '/'))
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++start;
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@ -1101,7 +1113,7 @@ name_split(char *name, int len)
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* the file would then expand on extract to //str. The len == 0 below
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* makes this special case follow the spec to the letter.
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*/
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if ((len >= TPFSZ) || (len == 0))
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if ((len > TPFSZ) || (len == 0))
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return(NULL);
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/*
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