* man2/socket.2 (.SH DESCRIPTION): Mention that the list of
address families is Linux-specific.
* man7/address_families.7 (.SH DESCRIPTION): Likewise.
Signed-off-by: Eugene Syromyatnikov <evgsyr@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
I need to get the TTL of UDP datagrams from userspace, so I set
the IP_RECVTTL socket option. And as promised by ip.7, I then get
IP_TTL messages from recvfrom. However, unlike what the manpage
promises, the TTL field gets passed as a 32 bit integer.
The following userspace code works:
uint32_t ttl32;
for (cmsg = CMSG_FIRSTHDR(msgh); cmsg != NULL; cmsg = CMSG_NXTHDR(msgh,cmsg)) {
if ((cmsg->cmsg_level == IPPROTO_IP) && (cmsg->cmsg_type == IP_TTL) &&
CMSG_LEN(sizeof(ttl32)) == cmsg->cmsg_len) {
memcpy(&ttl32, CMSG_DATA(cmsg), sizeof(ttl32));
*ttl=ttl32;
return true;
}
else
cerr<<"Saw something else "<<(cmsg->cmsg_type == IP_TTL) <<
", "<<(int)cmsg->cmsg_level<<", "<<cmsg->cmsg_len<<", "<<
CMSG_LEN(1)<<endl;
}
The 'else' field was used to figure out I go the length wrong.
Note from mtk:
Reading the source code also seems to confirm this, from
net/ipv4/ip_sockglue.c:
[[
static void ip_cmsg_recv_ttl(struct msghdr *msg, struct sk_buff *skb)
{
int ttl = ip_hdr(skb)->ttl;
put_cmsg(msg, SOL_IP, IP_TTL, sizeof(int), &ttl);
}
]]
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This best belongs at the end of the page, after the subsections
that already make some mention of user namespaces.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The text stated that the execve() capability transitions are not
performed for the same reasons that setuid and setgid mode bits
may be ignored (as described in execve(2)). But, that's not quite
correct: rather, the file capability sets are treated as empty
for the purpose of the capability transition calculations.
Also merge the new 'no_file_caps' kernel option text into the
same paragraph.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Clarify the "Capabilities and execution of programs by root"
section, and correct a couple of details:
* If a process with rUID == 0 && eUID != 0 does an exec,
the process will nevertheless gain effective capabilities
if the file effective bit is set.
* Set-UID-root programs only confer a full set of capabilities
if the binary does not also have attached capabilities.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Balbir pointed out that v1 delegation was not an accidental
feature.
Reported-by: Balbir Singh <bsingharora@gmail.com>
Reported-by: Marcus Gelderie <redmnic@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Use \(aq for ASCII apostrophes and \(ga for backtick,
as recommended by groff_man(7).
Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Clarify that SO_PASSCRED results in SCM_CREDENTIALS data in each
subsequently received message.
See https://bugzilla.kernel.org/show_bug.cgi?id=201805
Reported-by: Felipe Gasper <felipe@felipegasper.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Use "FAN_OPEN_PERM" consistently rather than "FAN_PERM_OPEN".
Signed-off-by: Anthony Iliopoulos <ailiopoulos@suse.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Because of setns() semantics, the parent of a process may reside
in the outer PID namespace. If that parent terminates, then the
child is adopted by the "init" in the outer PID namespace (rather
than the "init" of the PID namespace of the child).
Thus, in a scenario such as the following, if process M
terminates, P is adopted by the init process in the initial
PID namespace, and if P terminates, Q is adopted by the init
process in the inner PID namespace.
+---------------------------------------------+
| Initial PID NS |
| +---------------+ |
| +-+ | inner PID NS | |
| |1| | | |
| +-+ | +-+ | |
| | |1| | |
| | +-+ | |
| | | |
| +-+ setns(), fork() | +-+ | |
| |M|----------------------+--> |P| | |
| +-+ | +-+ | |
| | | fork() | |
| | v | |
| | +-+ | |
| | |Q| | |
| | +-+ | |
| +---------------+ |
+---------------------------------------------+
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Having the signals listed in three different tables reduces
readability, and would require more table splits if future
standards specify other signals.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The current tables of signal information are unwieldy,
as they try to cram in too much information.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
The previous location does not seem to be getting updated.
(For example, at the time of this commit, libcap-2.26
had been out for two months, but was not present at
http://www.kernel.org/pub/linux/libs/security/linux-privs.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
x86 and ARM are the most common architectures, but currently
are in the second subfield in the signal number lists.
Instead, swap that info with subfield 1, so the most
common architectures are first in the list.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This patch adds the signal numbers for parisc to the signal(7) man page.
Those parisc-specific values for the various signals are valid since the
Linux kernel upstream commit ("parisc: Reduce SIGRTMIN from 37 to 32 to
behave like other Linux architectures") during development of kernel 3.18:
http://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1f25df2eff5b25f52c139d3ff31bc883eee9a0ab
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Mention that the named constants (SECBIT_KEEP_CAPS and others)
are available only if the linux/securebits.h user-space header
is included.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
Eugene Syromyatnikov