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NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |EXAMPLES |NOTES |AUTHOR |SEE ALSO |COLOPHON | |
seccomp_attr_set(3) libseccomp Documentationseccomp_attr_set(3)seccomp_attr_set, seccomp_attr_get - Manage the seccomp filter attributes
#include <seccomp.h>typedef void * scmp_filter_ctx;enum scmp_filter_attr;int seccomp_attr_set(scmp_filter_ctxctx,enum scmp_filter_attrattr, uint32_tvalue);int seccomp_attr_get(scmp_filter_ctxctx,enum scmp_filter_attrattr, uint32_t *value); Link with-lseccomp.
Theseccomp_attr_set() function sets the different seccomp filter attributes while theseccomp_attr_get() function fetches the filter attributes. The seccomp filter attributes are tunable values that affect how the library behaves when generating and loading the seccomp filter into the kernel. The attributes are reset to their default values whenever the filter is initialized or reset viaseccomp_init(3) orseccomp_reset(3). The filter contextctx is the value returned by the call toseccomp_init(3). Validattr values are as follows:SCMP_FLTATR_ACT_DEFAULT The default filter action as specified in the call toseccomp_init(3) orseccomp_reset(3). This attribute is read-only.SCMP_FLTATR_ACT_BADARCH The filter action taken when the loaded filter does not match the architecture of the executing application. Defaults to theSCMP_ACT_KILLaction.SCMP_FLTATR_CTL_NNP A flag to specify if the NO_NEW_PRIVS functionality should be enabled before loading the seccomp filter into the kernel. Setting this to off (value == 0) results in no action, meaning that loading the seccomp filter into the kernel will fail if CAP_SYS_ADMIN is missing and NO_NEW_PRIVS has not been externally set. Defaults to on (value == 1).SCMP_FLTATR_CTL_TSYNC A flag to specify if the kernel should attempt to synchronize the filters across all threads onseccomp_load(3). If the kernel is unable to synchronize all of the thread then the load operation will fail. This flag is only available on Linux Kernel 3.17 or greater; attempting to enable this flag on earlier kernels will result in an error being returned. Defaults to off (value == 0).SCMP_FLTATR_API_TSKIP A flag to specify if libseccomp should allow filter rules to be created for the -1 syscall. The -1 syscall value can be used by tracer programs to skip specific syscall invocations, seeseccomp(2) for more information. Defaults to off (value == 0).SCMP_FLTATR_CTL_LOG A flag to specify if the kernel should log all filter actions taken except for theSCMP_ACT_ALLOWaction. Defaults to off (value == 0).SCMP_FLTATR_CTL_SSB A flag to disable Speculative Store Bypass mitigations for this filter. Defaults to off (value == 0).SCMP_FLTATR_CTL_OPTIMIZE A flag to specify the optimization level of the seccomp filter. By default libseccomp generates a set of sequential ´if´ statements for each rule in the filter.seccomp_syscall_priority(3) can be used to prioritize the order for the default cause. The binary tree optimization sorts by syscall numbers and generates consistentO(log n) filter traversal for every rule in the filter. The binary tree may be advantageous for large filters. Note thatseccomp_syscall_priority(3) is ignored when SCMP_FLTATR_CTL_OPTIMIZE == 2. The different optimization levels are described below:0Reserved value, not currently used.1Rules sorted by priority and complexity (DEFAULT).2Binary tree sorted by syscall number.SCMP_FLTATR_API_SYSRAWRC A flag to specify if libseccomp should pass system error codes back to the caller instead of the default -ECANCELED. Defaults to off (value == 0).SCMP_FLTATR_CTL_WAITKILL A flag to specify if libseccomp should request wait killable semantics when possible. Defaults to off (value == 0).
Returns zero on success or one of the following error codes on failure:-EACCES Setting the attribute with the given value is not allowed.-EEXIST The attribute does not exist.-EINVAL Invalid input, either the context or architecture token is invalid.-EOPNOTSUPP The library doesn't support the particular operation.
#include <seccomp.h> int main(int argc, char *argv[]) { int rc = -1; scmp_filter_ctx ctx; ctx = seccomp_init(SCMP_ACT_ALLOW); if (ctx == NULL) goto out; /* ... */ rc = seccomp_attr_set(ctx, SCMP_FLTATR_ACT_BADARCH, SCMP_ACT_TRAP); if (rc < 0) goto out; /* ... */ out: seccomp_release(ctx); return -rc; }While the seccomp filter can be generated independent of the kernel, kernel support is required to load and enforce the seccomp filter generated by libseccomp. The libseccomp project site, with more information and the source code repository, can be found athttps://github.com/seccomp/libseccomp. This tool, as well as the libseccomp library, is currently under development, please report any bugs at the project site or directly to the author.
Paul Moore <paul@paul-moore.com>
seccomp_init(3),seccomp_reset(3),seccomp_load(3),seccomp(2)
This page is part of thelibseccomp (high-level API to the Linux Kernel's seccomp filter) project. Information about the project can be found at ⟨https://github.com/seccomp/libseccomp⟩. If you have a bug report for this manual page, see ⟨https://groups.google.com/d/forum/libseccomp⟩. This page was obtained from the project's upstream Git repository ⟨https://github.com/seccomp/libseccomp⟩ on 2025-08-11. (At that time, the date of the most recent commit that was found in the repository was 2025-05-09.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which isnot part of the original manual page), send a mail to man-pages@man7.orgpaul@paul-moore.com 21 September 2022seccomp_attr_set(3)Pages that refer to this page:seccomp_merge(3), seccomp_rule_add(3)
HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |